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 salts salts and their classification acids, bases and salts chemistry

Which of the following does NOT form an acidic salt?

  1. Phosphoric acid

  2. Carbonic acid

  3. Hydrochloric acid

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

An acidic salt is formed by the partial replacement of replaceable hydrogen ions from a polybasic acid. Carbonic acid (H2CO3) is a weak acid that typically dissociates completely or forms neutral salts, whereas others like phosphoric or sulphuric acids have multiple replaceable hydrogens allowing for acidic salt formation.

Multiple choice salts salts and their classification acids, bases and salts chemistry

According to Lewis theory, neutralisation is the :

  1. transfer of proton from acid to base

  2. transfer of proton from base to acid

  3. transfer to electron pair from acid to base

  4. transfer of electron pair from base to acid
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

According to Lewis theory, neutralization is the transfer of electron pair from base to acid.

Multiple choice chemistry ionic equilibrium introduction to ionic equilibria in solution ionic equilibrium in solution ionisation of weak acids and weak bases

$pK _a$ values of four acids are given below at $25^oC$. Indicate the strongest acid.

  1. 2.0

  2. 3.0

  3. 2.5

  4. 4.0
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

$Ka$ represents the ionisation constant of an acid. It is a measure of the strength of the acid, provided the temperature remains constant.

    $pKa=-log(Ka)$

When $pKa=2$
           $2=-log(Ka)$
           $Ka=0.01$

When $pKa3$
           $3=-log(Ka)$
           $Ka=0.001$

Similarly, as $pKa $ values increase, $Ka$ value decrease and the acid becomes less strong. Hence smaller the $pKa$ value larger the $Ka$ value and hence stronger the acid.

So, the correct option is $A$

Multiple choice chemistry introduction to acid and base neutralisations in everyday life acids and bases in daily life neutralisation reaction

Which of the following base is used as antacid to neutralize stomach acidity?

  1. ${ Mg(OH) } _{ 2 }$
  2. $KOH$
  3. ${ Ca(OH) } _{ 2 }$
  4. $NaOH$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Magnesium hydroxide is also known as milk of magnesia and it is a common component of antacids and laxatives. It interferes with the absorption of folic acid and iron. It carries away much of the body's supply of potassium and neutralizes the stomach acid.

Multiple choice chemistry introduction to acid and base neutralisations in everyday life acids and bases in daily life neutralisation reaction

Which acid is used in dentistry and orthodontics as an etching solution?

  1. Tartaric acid

  2. Phosphoric acid

  3. Carbonic acid

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

Phosphoric acid is used in dentistry and orthodontics as an etching solution, to clean and roughen the surfaces of teeth where dental appliances or fillings will be placed. Phosphoric acid is also an ingredient in over-the-counter anti-nausea medications that also contain high levels of sugar (glucose and fructose). This acid is also used in many teeth whiteners to eliminate plaque that may be on the teeth before application.

Multiple choice chemistry introduction to acid and base neutralisations in everyday life acids and bases in daily life neutralisation reaction

The acidic behavior of lakes and oceans can be neutralized by:

  1. $NaOH$
  2. $HCl$
  3. $CaCO _3$
  4. $Ca(OH) _2$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Lakes and oceans can become acidic due to acid rain. This increases the acidity of such bodies and affects the aquatic life. To neutralize this acidic behavior of lakes and oceans, calcium carbonate $(CaCO _3)$ is used.

Multiple choice chemistry introduction to acid and base neutralisations in everyday life acids and bases in daily life neutralisation reaction

Toothpaste is _________  in nature.

  1. acidic

  2. basic

  3. neutral

  4. Both (A) and (B)
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The pH in our mouth is 5.5 which is slightly acidic. If the pH in our mouth decreases it results in tooth decay due to formation of certain acids. Toothpaste is basic in nature which neutralizes the acid and protects from tooth decay.

Multiple choice chemistry introduction to acid and base neutralisations in everyday life acids and bases in daily life neutralisation reaction

Using toothpaste in daily life is the example of _________.

  1. acidic reaction

  2. basic reaction

  3. neutralization reaction

  4. none of these
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Toothpaste is slightly basic is nature (pH ~ 8). The acid produced on the tooth enamel (commonly known as acid erosion) is neutralised by the toothpaste, cleaning your teeth. Hence, usage of toothpaste is the example of a neutralisation reaction.

Multiple choice chemistry introduction to acid and base neutralisations in everyday life acids and bases in daily life neutralisation reaction

Acids and bases are important because of :

  1. their use in industry

  2. their effects on human health

  3. their effects on farmer's crops

  4. their use in neutralization to form salts
Reveal answer Fill a bubble to check yourself
A,B,C,D Correct answer
Explanation
1. Acid and base are commonly used in industry on a large scale. For example, The steel industry uses hydrochloric acid to clean metal sheets before processing. On the other side of the pH scale, paper manufacturers make use of sodium hydroxide to remove lignin from paper pulp.

2. Both these are also important for the human body. Our kidneys and lungs work to maintain the acid-base balance. Acids are very lethal if not taken care of for the human body and causes like excessive skin problems, cramping, tooth decay, ligament problems, and even cancers.

3. The acid attack associated with a chemical change in the soil that can restrict the availability of essential plant nutrients and increase the availability of toxic elements. It is known as Soil acidity affects which totally affects the growth and nutritional values of crops.

4. All acid and base react with each other and resulting in a neutralization reaction by forming a salt and water like
$HCl + NaOH \to NaCl (salt) + H _2O (water).$

Thus all given options are correct.
Multiple choice chemistry introduction to acid and base neutralisations in everyday life acids and bases in daily life neutralisation reaction

Which acids/ bases are used for the following?
(i) To neutralize sting of wasps
(ii) In alkaline batteries
(iii) Manufacturing of soap

  1. (i) $CH _3CHO$ (ii) $CsOH$ (iii) $Ca(OH) _2$
  2. (i) $CH _3COOH$ (ii) $CuSO _4$ (iii)$ Ba(OH) _2$
  3. (i) $CH _3COOH$ (ii) $KOH$ (iii)$ NaOH$

  4. None of these
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation
  1. Formic acid is produced by ants and acetic acid is used as anti-wasp agents.
    2. In alkali batteries a base is used as an electrolyte which gives hydroxyl ions in solution.
    3. Manufacturing of soap requires an alkali like $NaOH$ and long chain of fatty acids like sodium stearate to form an ester or sodium acetate salt.
Multiple choice chemistry air and water pollution control smoke, dust and other air pollutants, acid rain air pollutants and its effects air and air pollution

Which one of these are known as prussic acid?

  1. $HCN$
  2. $HF$
  3. $NH _3$
  4. $PH _3$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Hydrogen cyanide $(HCN)$, sometimes called prussic acid, is a chemical compound with the chemical formula $HCN$. 

It is colourless, extremely poisonous and flammable liquid that boils slightly above room temperature. $HCN$ is produced on an industrial scale and is a highly valuable precursor to many chemical compounds ranging from polymers to pharmaceuticals.