Which will not affect the degree of ionisation?

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

The incorrect relation for isohydric solutions is $:-$

When $100 \ mL$ of $0.1 \ M$ $NaCN$ solution is titrated with $0.1 \ M$ $HCl$ solution,the variation of $pH$ of the solution with the volume of $HCl$ added will be:

For the reaction in aqueous solution $Zn^{2+} + X^{-} \rightleftharpoons ZnX^{+}$,the $K_{eq}$ is greatest when $X$ is

Arrange the following resultant mixtures in increasing order of their pH values:
$A$. $10 \text{ mL } 0.2 \text{ M } Ca(OH)_2 + 25 \text{ mL } 0.1 \text{ M } HCl$
$B$. $10 \text{ mL } 0.01 \text{ M } H_2SO_4 + 10 \text{ mL } 0.01 \text{ M } Ca(OH)_2$
$C$. $10 \text{ mL } 0.1 \text{ M } H_2SO_4 + 10 \text{ mL } 0.1 \text{ M } KOH$
Choose the correct answer from the options given below: