Chemistry

Acids and Bases

594 Questions

Acids and bases questions cover the chemical properties, common examples, and theoretical concepts of acidic and basic substances. Topics include identifying proton acceptors, recognizing amphoteric substances, and knowing the sources of everyday organic acids. These foundational chemistry questions are common across SSC, banking, and railways examinations.

Acid and base propertiesOrganic acidsAmphoteric substancesProton donors and acceptorsChemical formulas

Acids and Bases Questions

Multiple choice

Which of the following is diprotic acid?

  1. Phosphomolybdic acid

  2. Phosphotungstic acid

  3. Phosphorous acid

  4. Phosphoric acid
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Phosphorous acid is a compound with the formula H3PO3. This acid is diprotic (readily ionizes two protons), not triprotic as might be suggested by this formula. Phosphorous acid is as an intermediate in the preparation of other phosphorus compounds.

Multiple choice

Acidity regulators are food additives which changes or maintains pH .Which of the following compounds is a acidity regulator?

  1. Gluconic acid

  2. Gibberellic acid

  3. Geraniol

  4. γ-Hydroxybutyric acid
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Gluconic acid occurs naturally in fruit, honey, kombucha tea and wine. As a food additive it is an acidity regulator. It is also used in cleaning products where it dissolves mineral deposits especially in alkaline solution.

Multiple choice

Which of the following statement is/are not correct about hydrochloric Acid (HCI)? I. Is a solution of hydrogen chloride (a colorless acidic gas) in water
II. Is corrosive strong multi basic forming only one series of salts the chlorides III. Is used for recovery of zinc from scrap iron IV. Cannot be used for the stomachs of animals of chlorine V. Is also produced in the stomachs of animals for the purpose of digestion

  1. I, II and III

  2. II and IV

  3. V only

  4. III and V
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Statement II incorrectly describes HCl as 'multi basic' when it's actually monobasic. Statement IV is grammatically incorrect and nonsensical. HCl is monobasic (forms one series of salts), and is naturally produced in the stomach for digestion.

Multiple choice

Which of the following is not a true equilibrium constant?

  1. An acid dissociation constant

  2. The binding constant

  3. A dissociation constant

  4. Conditional constants
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Conditional constants, also known as apparent constants, are concentration quotients which are not true equilibrium constants but can be derived from them. A very common instance is where pH is fixed at a particular value.

Multiple choice

H2SO4 is

  1. hydrochloric acid

  2. sulphuric acid

  3. nitric acid

  4. benzoic acid
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

H2SO4 is the chemical formula for sulphuric acid, a strong mineral acid. Hydrochloric acid is HCl, nitric acid is HNO3, and benzoic acid is C7H6O2.

Multiple choice

The vinegar used in homes is basically

  1. citric acid

  2. acetic acid

  3. tartaric acid

  4. hydrochloric acid
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Household vinegar is essentially a solution of acetic acid in water, typically containing 4-8% acetic acid by volume. Citric acid is found in citrus fruits, tartaric acid occurs naturally in grapes and tamarind, while hydrochloric acid is a strong mineral acid used in laboratories and industry - none of these are the primary component of vinegar. Acetic acid gives vinegar its characteristic sour taste and smell.

Multiple choice

The element common to all acids is

  1. oxygen

  2. hydrogen

  3. nitrogen

  4. sulphur
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

All acids contain hydrogen ions (H+). When acids dissolve in water, they release H+ ions, which is why hydrogen is the defining element present in all acidic compounds. Oxygen is not present in all acids (e.g., HCl).

Multiple choice

Vinegar is the commercial name of

  1. oxalic acid

  2. hydrochloric acid

  3. acetic acid

  4. all of the obove
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Vinegar is the commercial name for dilute acetic acid solution, typically containing 5-8% acetic acid (CH3COOH) in water. Acetic acid gives vinegar its characteristic sour taste and pungent odor. Oxalic acid and hydrochloric acid are different chemicals with different properties and uses.

Multiple choice

Among the following the strongest acids is

  1. ClCH2COOH

  2. Cl2CHCOOH

  3. CH<font color="#333333">3</font>COOH

  4. Cl3CCOOH
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The acidity of haloacetic acids increases with the number of electron-withdrawing halogen atoms. More chlorines stabilize the conjugate base better by dispersing the negative charge through inductive effect. Trichloroacetic acid (Cl3CCOOH) is strongest because it has three -I effect groups, followed by dichloro, then chloro, then unsubstituted acetic acid.

Multiple choice

Which of the following statements are incorrect? P. Basicity of phosphorous acid is three. Q. The bleaching action of SO2 is due to its reducing action. R. Sulphur acts as an oxidising agent in the vulcanisation of rubber. S. The C-C bond length in graphite is shorter than that in diamond.

  1. P and Q

  2. P and R

  3. Q and R

  4. Q and S

  5. R and S
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

This option is correct because the basicity of phosphorous acid (H3PO3) is two and sulphur acts as cross linking agent in the vulcanisation of rubber.

Multiple choice

A lemon is sour because of

  1. citric acid

  2. oxalic acid

  3. acetic acid

  4. None of these
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Lemons contain citric acid (C6H8O7), which gives them their characteristic sour taste. Citric acid is a natural preservative found in citrus fruits. Oxalic acid is in spinach (causes metallic taste), acetic acid is in vinegar. Citric acid is the correct answer.

Multiple choice

Which of the following sets represents only soft acids?

  1. Ni(0), Cu(I), Mg(II), Al(III)

  2. Ni(0), Cu(I), Hg(II), Pt(II)

  3. Cu(I), Cu(II), Hg(II), Fe(III)

  4. Ag(I), Au(I), Zn(II), Mg(II)

  5. Li(I), Ca(II), Al(III), Si(IV)
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Ni(0), Cu(I), Hg(II) and Pt(II) all are soft acids.