$A$ $0.1 \ N$ solution of an acid at room temperature has a degree of ionisation $0.1$. The concentration of $OH^{-}$ would be

Which of the following absorbs oxygen rapidly?

Identify the correct statements from the following.
$(A)$ The ionic product of water at $100^{\circ} C$ is $< 10^{-14}$.
$(B)$ $pH$ of a solution decreases with increasing temperature.
$(C)$ $NaH_2PO_4$ on hydrolysis gives a basic solution.
$(D)$ $NH_3$ can act both as Bronsted acid and base.

Blue litmus turns red in the following mixture of acid and base:

Calculate the $pH$ of the resultant mixtures:
$(a)$ $10 \, mL$ of $0.2 \, M \, Ca(OH)_{2} + 25 \, mL$ of $0.1 \, M \, HCl$
$(b)$ $10 \, mL$ of $0.01 \, M \, H_{2}SO_{4} + 10 \, mL$ of $0.01 \, M \, Ca(OH)_{2}$
$(c)$ $10 \, mL$ of $0.1 \, M \, H_{2}SO_{4} + 10 \, mL$ of $0.1 \, M \, KOH$

The moles of $H^{+}$ from $H_2O$ alone in a $1 \ L$,$\sqrt{5} \times 10^{-7} \ M$ $HCl$ solution at $25 \ ^\circ C$ is ( $\sqrt{5} = 2.23$ )