12.2 gm of sodium salt of weak monobasic acid $\left(K_a=\right.\left.{10}^{-6}\right)$ is dissolved in 100 ml of water and pH of resulting solution is found to be 10 at 25° C. Then which of the following is correct?

Molar mass of salt is $122 \mathrm{gm}/\mathrm{mole}$

pH of solution when 1 gm of same weak acid is dissolved in 1 $\mathrm{litre}$ of water is 4.

$K_b$ of conjugate base of same weak acid is ${10}^{-8}$

Molar mass of conjugate base of same weak acid is 99.