Question

Van't Hoff's factor for $0.01M$ aqueous solution of acetic acid is $1.04,$ then $pH$:

• A. $3.4$
• B. $6.4$
• C. $9.6$
• D. $10.6$

Answer 1

The correct option is A $3.4$

Given : $i=1.04$

we know $i=1+\alpha (n-1)$

Here $n=2$, so $i=1+\alpha$

$\alpha =0.04$

$\left[H^{+}\right]=C\alpha =0.01\left(0.04\right)=4\times {10}^{-4}$

$pH=-\log \left[H^{+}\right]=-\log [4\times {10}^{-4}]=4-\log 4$

$pH=4-0.6=3.4$