Acids and bases

A solution is prepared by mixing 0.01 mol each of $\ce{H2CO3}$, $\ce{NaHCO3}$, $\ce{Na2CO3}$, and NaOH in 100 mL of water. $p$H of the resulting solution is _____.

[Given: $pK_{a1}$ and $pK_{a2}$ of $\ce{H2CO3}$ are 6.37 and 10.32, respectively; log 2 = 0.30]

Given below are two statements one is labelled as Assertion A and the other is labelled as Reason R :

Assertion A : The amphoteric nature of water is explained by using Lewis acid/base concept.

Reason R : Water acts as an acid with $\mathrm{NH_3}$ and as a base with $\mathrm{H_2S}$.

In the light of the above statements choose the correct answer from the options given below :

$K_{a_1}$, $K_{a_2}$ and $K_{a_3}$ are the respective ionization constants for the following reactions (a), (b), and (c).

(a) $\mathrm{H_2C_2O_4\rightleftharpoons H^++HC_2O_4^-}$

(b) $\mathrm{HC_2O_4^-\rightleftharpoons H^++C_2O_4^{2-}}$

(c) $\mathrm{H_2C_2O_4\rightleftharpoons2H^++C_2O_4^{2-}}$

The relationship between $K_{a_1}$, $K_{a_2}$ and $K_{a_3}$ is given as

Given below are two statements: one is labelled as Assertion A and the other is labelled as Reason R.

Assertion A: Boric acid is a weak acid.

Reason R: Boric acid is not able to release $\mathrm{H^+}$ ion on its own. It receives $\mathrm{OH^-}$ ion from water and releases $\mathrm{H^+}$ ion.

In the light of the above statements, choose the most appropriate answer from the options given below.

In the following reactions, ZnO is respectively acting as a/an :

(a) $\ce{ZnO + Na2O -> Na2ZnO2}$

(b) $\ce{ZnO + CO2 -> ZnCO3}$

The correct statement(s) for orthoboric acid is/are

The conjugate base of hydrazoic acid is :

The total number of diprotic acids among the following is

$\ce{H3PO4}$, $\ce{H2SO4}$, $\ce{H3PO3}$, $\ce{H2CO3}$, $\ce{H2S2O7}$, $\ce{H3BO3}$, $\ce{H3PO2}$, $\ce{H2CrO4}$, $\ce{H2SO3}$

STATEMENT-1: In water, orthoboric acid behaves as a weak monobasic acid.

because

STATEMENT-2: In water, orthoboric acid acts as a proton donor.