Acids Bases Salts and Solutions Competitive Exams
100 questions · General Science
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Question 1 of 100
An acid that only partially ionises in water is called a:
ExplanationAcetic acid and carbonic acid are common examples of weak acids.
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Question 2 of 100
On the pH scale, bases have a value:
ExplanationA pH above 7 indicates a basic (alkaline) solution.
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Question 3 of 100
The chemical formula of sodium hydroxide is:
ExplanationSodium hydroxide is a strong base also called caustic soda.
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Question 4 of 100
According to the Lewis theory, a base is defined as a substance that:
ExplanationLewis bases supply electron pairs to form new bonds.
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Question 5 of 100
When an acid reacts with a reactive metal, the products are typically a salt and:
ExplanationAcid + metal gives a salt plus hydrogen gas, often seen as bubbles.
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Question 6 of 100
The air we breathe is best described chemically as a:
ExplanationAir is a homogeneous mixture mainly of nitrogen, oxygen and other gases.
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Question 7 of 100
Bases generally taste bitter and feel:
ExplanationThis slippery feel is a characteristic physical property of bases.
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Question 8 of 100
The substance that dissolves in a solvent to form a solution is called the:
ExplanationSugar dissolved in water is an example of a solute.
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Question 9 of 100
Testing a solution with barium chloride, producing a white precipitate, confirms the presence of:
ExplanationBarium sulfate forms as an insoluble white precipitate in this test.
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Question 10 of 100
When an acid reacts with a metal carbonate, the products are a salt, water and:
ExplanationThis reaction produces CO2, which can turn limewater milky.
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Question 11 of 100
The acid present in vinegar is:
ExplanationVinegar is a dilute solution of acetic (ethanoic) acid.
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Question 12 of 100
Titration is a laboratory technique mainly used to determine:
ExplanationA solution of known concentration is used to find an unknown one.
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Question 13 of 100
The amount of solute present in a given amount of solvent or solution is called its:
ExplanationConcentration describes how much solute is present relative to solution.
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Question 14 of 100
The chemical name for baking soda is:
ExplanationBaking soda, NaHCO3, is used in cooking and as a mild antacid.
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Question 15 of 100
The chemical formula of sulphuric acid is:
ExplanationSulphuric acid is a strong, dense, highly corrosive mineral acid.
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Question 16 of 100
On a universal indicator chart, a strong base typically appears:
ExplanationHigher pH values are generally shown in blue-purple shades.
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Question 17 of 100
A salt formed from a strong acid and a weak base, such as ammonium chloride, is typically:
ExplanationThe weak base component makes the resulting salt solution slightly acidic.
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Question 18 of 100
Bases turn red litmus paper:
ExplanationThis colour change is a standard test to identify bases.
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Question 19 of 100
The reaction of a base with an acid, producing salt and water, is called:
ExplanationBoth acids and bases describe this same type of reaction.
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Question 20 of 100
Phenolphthalein, a common acid-base indicator, is typically pink in base and:
ExplanationThis sharp colour change makes it popular for titrations.
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Question 21 of 100
Common salt (sodium chloride) is widely used in food mainly to:
ExplanationSalt inhibits microbial growth, helping preserve food, and adds taste.
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Question 22 of 100
A solution that resists changes in pH when small amounts of acid or base are added is a:
ExplanationBuffers help maintain stable pH, important in blood and industry.
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Question 23 of 100
For gases dissolving in liquids, solubility generally:
ExplanationThis is why warm fizzy drinks lose their dissolved carbon dioxide faster.
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Question 24 of 100
The acid present in sour milk and yogurt is:
ExplanationBacteria ferment milk sugar into lactic acid, causing sourness.
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Question 25 of 100
A base that is soluble in water is specifically called an:
ExplanationAll alkalis are bases, but not all bases dissolve in water.
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Question 26 of 100
An acid that ionises (dissociates) almost completely in water is called a:
ExplanationStrong acids like HCl, H2SO4 and HNO3 ionise nearly completely.
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Question 27 of 100
According to the Bronsted-Lowry theory, an acid is defined as a substance that:
ExplanationThis definition broadened the Arrhenius concept beyond water-based solutions.
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Question 28 of 100
Colligative properties of a solution, such as boiling point elevation, depend mainly on the:
ExplanationColligative properties depend on particle count, not what the particles are.
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Question 29 of 100
The strong acid commonly used in car (lead-acid) batteries is:
ExplanationDilute sulphuric acid serves as the electrolyte in lead-acid batteries.
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Question 30 of 100
A solution whose concentration is precisely known and used as a reference in titrations is called a:
ExplanationStandard solutions are prepared with carefully measured amounts of solute.
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Question 31 of 100
Potassium nitrate, used in fertilisers and gunpowder, is commonly called:
ExplanationSaltpetre has historically been important in both agriculture and explosives.
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Question 32 of 100
Adding more solvent to a solution to reduce its concentration is called:
ExplanationDilution lowers the concentration without removing any solute.
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Question 33 of 100
A solution with a pH of exactly 7 at room temperature is considered to be:
ExplanationPure water at room temperature has a pH of 7, the neutral point.
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Question 34 of 100
Baking soda (sodium bicarbonate) in solution is:
ExplanationIt is a weak base, which is why it can neutralise mild acidity.
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Question 35 of 100
Tannic acid, which gives a characteristic astringent taste, is commonly found in:
ExplanationTannic acid contributes to the bitterness and colour of tea.
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Question 36 of 100
Molarity is a common unit of concentration expressed as moles of solute per:
ExplanationMolarity (mol/L) is widely used in chemistry to express concentration.
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Question 37 of 100
Water molecules chemically bound within the crystal structure of a salt are called:
ExplanationCopper sulfate crystals, for example, contain water of crystallisation.
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Question 38 of 100
The chemical name for common table salt is:
ExplanationTable salt, NaCl, is formed from sodium and chlorine ions.
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Question 39 of 100
The reaction of a salt with water, which can affect the resulting solution's pH, is called:
ExplanationSalt hydrolysis explains why some salt solutions are acidic or basic.
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Question 40 of 100
Lime water used in chemistry tests is a solution of:
ExplanationLime water turns milky in the presence of carbon dioxide.
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Question 41 of 100
The acid present in citrus fruits such as lemon is:
ExplanationCitric acid gives citrus fruits their characteristic sour taste.
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Question 42 of 100
A homogeneous mixture formed by dissolving a solute in a solvent is called a:
ExplanationSolutions have uniform composition throughout.
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Question 43 of 100
On the standard pH scale used in chemistry, values typically range from:
ExplanationValues below 7 are acidic, above 7 are basic, with 7 being neutral.
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Question 44 of 100
A substance that can react as both an acid and a base is described as:
ExplanationWater and aluminium hydroxide are classic amphoteric substances.
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Question 45 of 100
The salt formed from the reaction of hydrochloric acid and sodium hydroxide is:
ExplanationHCl + NaOH produces sodium chloride and water.
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Question 46 of 100
Tincture of iodine, used as an antiseptic, is an example of a solution of a solid dissolved in:
ExplanationIodine is dissolved in an alcohol-based solvent to form this tincture.
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Question 47 of 100
A solution that has dissolved the maximum solute possible at a given temperature is called:
ExplanationNo more solute will dissolve in a saturated solution at that temperature.
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Question 48 of 100
The chemical formula of nitric acid is:
ExplanationNitric acid is a strong acid widely used in industry and labs.
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Question 49 of 100
A base that only partially dissociates in water is called a:
ExplanationAmmonium hydroxide is a typical example of a weak base.
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Question 50 of 100
Ammonia gas dissolved in water forms the weak base:
ExplanationNH3 + H2O reversibly forms ammonium hydroxide (NH4OH).
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Question 51 of 100
According to the Lewis theory, an acid is defined as a substance that:
ExplanationThe Lewis definition is the broadest, covering reactions without protons.
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Question 52 of 100
Concentrated sulphuric acid is widely used industrially mainly as a:
ExplanationIt strongly absorbs water, making it useful for removing moisture.
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Question 53 of 100
Sodium hydroxide, used in making soap, is commonly known as:
ExplanationSodium hydroxide (NaOH) is a strong base used in soap manufacture.
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Question 54 of 100
A salt bridge in an electrochemical cell allows the flow of ions to balance charge between:
ExplanationSalt bridges maintain electrical neutrality as the reaction proceeds.
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Question 55 of 100
The reaction between an acid and a base that produces a salt is called:
ExplanationThis reaction is the standard method for forming many common salts.
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Question 56 of 100
In soap-making (saponification), alkalis react with fats and oils to form:
ExplanationSaponification breaks down fats using a strong base like NaOH.
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Question 57 of 100
According to the Bronsted-Lowry theory, a base is defined as a substance that:
ExplanationThis definition explains basic behaviour even without hydroxide ions.
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Question 58 of 100
The substance in which a solute dissolves is called the:
ExplanationWater is the most common solvent in everyday chemistry.
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Question 59 of 100
The chemical formula of hydrochloric acid is:
ExplanationHydrochloric acid is a solution of hydrogen chloride gas in water.
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Question 60 of 100
Water is often described as the universal solvent because it:
ExplanationWater's polarity allows it to dissolve many ionic and polar substances.
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Question 61 of 100
A salt that has lost its water of crystallisation upon heating is described as:
ExplanationAnhydrous salts contain no water molecules in their crystal structure.
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Question 62 of 100
The reaction of an acid with a base to form salt and water is called:
ExplanationNeutralisation reactions cancel out the acidic and basic properties.
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Question 63 of 100
Plaster of Paris, used in casts and moulds, is derived by heating:
ExplanationHeating gypsum removes most of its water, forming plaster of Paris.
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Question 64 of 100
A salt formed from a weak acid and a weak base, such as ammonium acetate, has a pH that is generally:
ExplanationSuch salts' pH depends on the relative strengths of the parent acid and base.
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Question 65 of 100
A solution that can still dissolve more solute at a given temperature is called:
ExplanationAdditional solute can still be added and dissolved in such a solution.
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Question 66 of 100
Carbonic acid, found in fizzy drinks, is formed when carbon dioxide dissolves in:
ExplanationCO2 + H2O forms the weak acid carbonic acid (H2CO3).
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Question 67 of 100
Milk of magnesia, used as an antacid, contains:
ExplanationIt neutralises excess stomach acid to relieve indigestion.
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Question 68 of 100
A substance that produces OH- ions (hydroxide ions) in water is called a:
ExplanationThis is the Arrhenius definition of a base.
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Question 69 of 100
The acid present in the human stomach, aiding digestion, is:
ExplanationGastric HCl helps break down food and kill harmful bacteria.
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Question 70 of 100
Sodium chloride, a salt of a strong acid and strong base, has a pH of approximately:
ExplanationSalts formed from a strong acid and strong base are neutral.
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Question 71 of 100
A base that dissociates almost completely in water is called a:
ExplanationSodium hydroxide and potassium hydroxide are common strong bases.
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Question 72 of 100
Two liquids that do not mix with each other, such as oil and water, are described as:
ExplanationImmiscible liquids separate into distinct layers rather than blending.
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Question 73 of 100
Testing for a carbonate ion with dilute acid produces a gas that turns limewater:
ExplanationThe gas released is carbon dioxide, which reacts with limewater.
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Question 74 of 100
Antacid tablets relieve heartburn mainly by:
ExplanationMild bases in antacids react with and reduce excess stomach HCl.
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Question 75 of 100
On the pH scale, acids have a value:
ExplanationA pH below 7 indicates an acidic solution.
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Question 76 of 100
A solution of copper sulfate characteristically appears:
ExplanationHydrated copper sulfate gives solutions their distinctive blue colour.
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Question 77 of 100
Epsom salt, used in bathing and as a laxative, is chemically known as:
ExplanationEpsom salt is magnesium sulfate, often used for sore muscles.
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Question 78 of 100
A salt formed from a strong acid and a strong base typically has a pH of about:
ExplanationSuch salts, like sodium chloride, are neutral in solution.
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Question 79 of 100
The chemical formula of potassium hydroxide is:
ExplanationPotassium hydroxide is used in making liquid soaps and batteries.
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Question 80 of 100
The ability of a substance to dissolve in a given solvent is called its:
ExplanationSolubility varies by substance, solvent, and temperature.
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Question 81 of 100
Liquids that mix completely in all proportions, such as water and alcohol, are called:
ExplanationMiscible liquids form a single uniform phase when combined.
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Question 82 of 100
An indicator that shows a range of colours corresponding to different pH values is called:
ExplanationUniversal indicator gives an approximate pH reading through its colour.
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Question 83 of 100
A salt formed from a weak acid and a strong base, such as sodium carbonate, is typically:
ExplanationThe strong base component makes the resulting salt solution slightly basic.
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Question 84 of 100
The compound formed, along with water, when an acid reacts with a base is called a:
ExplanationSalts are ionic compounds formed in acid-base neutralisation reactions.
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Question 85 of 100
Nitric acid is an important raw material in the manufacture of:
ExplanationNitric acid is key to producing ammonium nitrate and related products.
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Question 86 of 100
A substance that produces H+ ions (hydrogen ions) in water is called an:
ExplanationThis is the Arrhenius definition of an acid.
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Question 87 of 100
The acid responsible for the sting of ants and some insect bites is:
ExplanationFormic acid is injected by ants and some stinging insects.
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Question 88 of 100
Gypsum, used in making plaster and cement, is chemically known as:
ExplanationGypsum is a naturally occurring mineral form of calcium sulfate.
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Question 89 of 100
Acid rain is mainly caused by atmospheric pollutants such as sulphur dioxide and:
ExplanationThese gases react with water vapour in the air to form acids.
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Question 90 of 100
Acids turn blue litmus paper:
ExplanationThis colour change is a standard test to identify acids.
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Question 91 of 100
Alloys such as brass and steel are commonly classified as examples of:
ExplanationOne solid metal is dissolved uniformly within another in an alloy.
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Question 92 of 100
A common household base, found in some cleaning solutions, is:
ExplanationAmmonia solution is a mild alkali effective at cutting grease.
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Question 93 of 100
For most solid solutes dissolving in water, solubility generally:
ExplanationWarmer water usually dissolves more of most solid solutes.
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Question 94 of 100
Acids generally taste:
ExplanationSourness is a characteristic taste of acidic substances.
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Question 95 of 100
Washing soda, used in cleaning, is chemically known as:
ExplanationWashing soda (Na2CO3) is mildly alkaline and used in detergents.
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Question 96 of 100
The pH of a concentrated solution of a strong alkali like sodium hydroxide is typically close to:
ExplanationStrong alkalis sit at the high end of the 0-14 pH scale.
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Question 97 of 100
An unstable solution holding more dissolved solute than is normally possible is called:
ExplanationSupersaturated solutions can suddenly crystallise if disturbed.
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Question 98 of 100
Silver nitrate solution is commonly used in laboratories to test for the presence of:
ExplanationSilver nitrate reacts with chloride ions to form a white precipitate.
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Question 99 of 100
Ammonium chloride, commonly used in dry cell batteries, is a salt that is generally:
ExplanationIt forms from a strong acid and a weak base, making it slightly acidic.
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Question 100 of 100
Calcium hydroxide is commonly known as:
ExplanationSlaked lime is produced by adding water to quicklime (CaO).
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