Strength of Acids

IMPORTANT

Strength of Acids: Overview

This topic describes strong and weak acids with an experimental method to determine whether the given acid is a strong acid or a weak acid. It also highlights the methods to calculate the strength of acids.

Important Questions on Strength of Acids

EASY
IMPORTANT

In Figure - 1 and Figure - 2, equal moles of HA and BOH substances are added to the same volume of pure water at the same temperature. The equations for the solubility of these substances in water are given thereafter.

Question Image

 

(i) The number of moles of H+ vessel 1 equals the number of moles of OH- in vessel 2.

(ii) The electrical conductivity of HA (in water) is higher than that of BOH (in water).

(iii) The number of moles of OH-ions in HA (water) is greater than the number of moles of OH-ions in BOH (water).

Which of the statements out of I, II, III are correct? 

MEDIUM
IMPORTANT

Mineral acids are stronger acids than carboxylic acids because
1. Mineral acids are completely ionized in an aqueous solution.
2. Mineral acids are partially ionized in an aqueous solution.
3. Carboxylic acids are completely ionized in an aqueous solution.
4. Carboxylic acids are partially ionized in an aqueous solution.
Codes:

EASY
IMPORTANT

Which of the following gives the correct increasing order of acidic strength?

EASY
IMPORTANT

A sample of soil is mixed with water and allowed to settle.The clear supernatant solution turns the pH paper yellowish-orange.Which of the following would change the colour of this pH paper to greenish-blue?

EASY
IMPORTANT

The aqueous solution of which of the following substance is a good conductor of electricity?

MEDIUM
IMPORTANT

The Ka values of formic acid and acetic acid are respectively 1.77×10-4 and 1.75×10-5. The ratio of acid strength of 0.1 N acids is

EASY
IMPORTANT

The acidic and basic strength of solution is based on _______________ ion concentration.

EASY
IMPORTANT

4.76, 4.19, 0.23 and 3.41 are the pKa values of  four carboxylic acids respectively. What is the pKa value of strongest carboxylic acid among them?

MEDIUM
IMPORTANT

Which of the following is expected to be most highly ionised in water?

HARD
IMPORTANT

HClO4,HNO3 and HCl are all strong acids in aqueous solution. In glacial acetic acid medium, their acid strength is such that

EASY
IMPORTANT

Equimolar solutions of HF, HCOOH and HCN at 298 K have the values of Ka as 6.8×10-4,1.8×10-4 and 4.8×10-9 respectively. What will be the order of their acidic strength?

EASY
IMPORTANT

The dissociation constant of two weak acids are  K a 1 and K a 2 respectively. Their relative strength of identical concentration  is-

EASY
IMPORTANT

The pKa values of four carboxylic acids are 4.76, 4.19, 0.23 and 3.41 respectively. What is the pKa value of strongest carboxylic acid among them?

EASY
IMPORTANT

The ratio of acid strength of HOCN and HCN is about

Given Ka of HOCN= 1.2 × 104 and Ka of HCN=4.2 × 1010

MEDIUM
IMPORTANT

Four species are listed below

1. HCO3-

2. H3O+

3. HSO4-

4. HSO3F

Which one of the following is the correct sequence of their acid strength?

EASY
IMPORTANT

CH3COOH is weaker acid than H2SO4. It is due to