Question

In the following observation.

Acid	$K _{a_{1}}$	$K _{a_{2}}$	$(X)$
Oxalic acid	$5.9 \times 10^{-2}$	$6.4 \times 10^{-5}$
Ascorbic acid	$7.4 \times 10^{-4}$	$1.6 \times 10^{-12}$
Sulphurous acid	$1.7 \times 10^{-2}$	$6.4 \times 10^{-8}$
$(Y)$	Very large	$1.2 \times 10^{-2}$
Carbonic acid	$4.3 \times 10^{-7}$	$(Z)$
Citric acid	$7.4 \times 10^{-4}$	$1.7 \times 10^{-5}$	$4.0 \times 10^{-7}$
Phosphoric acid	$7.5 \times 10^{-3}$	$6.2 \times 10^{-8}$	$4.2 \times 10^{-13}$

$X, Y$ and $Z$ respectively are

• A. $K=K_{a_{1}} \times K_{a_{2}}$, phosphorous acid, $6.5 \times 10^{-11}$
• B. $K_{a_{3}}$, phosphorous acid, $6.5 \times 10^{-11}$
• C. $K=K_{a_{1}} \times K_{a_{2}}$, sulphuric acid, $5.6 \times 10^{-11}$
• D. $K_{a_{3}}$, sulphuric acid, $5.6 \times 10^{-11}$

Answer 1

Answer: (D)

Correct answer is (d) $K_{a_{3}}$, sulphuric acid, $5.6 \times 10^{-11}$