Question

Cal poh of 10*-2 m monobasic acid if value of kw at 90°c is 10*-12

Answer 1

Answer: pOH of monobasic acid is 10.

Explanation: We are given a monobasic acid:

              $HA\rightarrow H^++A^-$

at t=0     $10^{-2}$      0       0

at t=t       0     $10^{-2}$    $10^{-2}$

$[H^+]=10^{-2}M$

pH can be calculated as:

$pH=-log[H^+]$

$pH=-log(10^{-2})$

pH = 2

We are given the value of $K_w$, so $pK_w$ can be calculated by:

$pK_w=-log(K_w)$

$pK_w=-log(10^{-12})$

$pK_w=12$

And we know,

$pK_w=pH+pOH$

$12=2+pOH$

pOH = 10