What is the $[OH^{-}]$ in the final solution prepared by mixing $20.0 \ mL$ of $0.050 \ M \ HCl$ with $30.0 \ mL$ of $0.10 \ M \ Ba(OH)_2$? $...... \ M$

Which will not affect the degree of ionisation?

What is the percent dissociation of $NH_4OH$ if the molar conductance at zero concentration for $NH_4Cl, NaCl$,and $NaOH$ are $130, 109$,and $213 \ S \ cm^2 \ mol^{-1}$ respectively,and the molar conductivity of $0.01 \ M \ NH_4OH$ is $9.0 \ S \ cm^2 \ mol^{-1}$?

Arrange the following solutions in the decreasing order of $pOH$:
$A$. $0.01 \ M \ HCl$
$B$. $0.01 \ M \ NaOH$
$C$. $0.01 \ M \ CH_3COONa$
$D$. $0.01 \ M \ NaCl$

$A$ $20 \ mL$ sample of a $0.1 \ M$ solution of the weak monoprotic acid $HA$ is titrated with $0.25 \ M \ NaOH$. The volume of $NaOH$ solution required to reach the equivalence point is: ............. $mL$

In which of the following mixed aqueous solutions,$pH = pK_{a}$ at equilibrium?
$(1)$ $100 \ mL$ of $0.1 \ M \ CH_{3}COOH + 100 \ mL$ of $0.1 \ M \ CH_{3}COONa$
$(2)$ $100 \ mL$ of $0.1 \ M \ CH_{3}COOH + 50 \ mL$ of $0.1 \ M \ NaOH$
$(3)$ $100 \ mL$ of $0.1 \ M \ CH_{3}COOH + 100 \ mL$ of $0.1 \ M \ NaOH$
$(4)$ $100 \ mL$ of $0.1 \ M \ CH_{3}COOH + 100 \ mL$ of $0.1 \ M \ NH_{3}$