How many $g$ of $KOH$ are required to completely neutralize $12.6 \, g$ of $HNO_3$?

Sodium oxide reacts with water to produce sodium hydroxide. $20.0 \ g$ of sodium oxide is dissolved in $500 \ mL$ of water. Neglecting the change in volume,the concentration of the resulting $NaOH$ solution is $........ \times 10^{-1} \ M.$ (Nearest integer)
[Atomic mass $: Na=23.0, O=16.0, H=1.0]$

The composition of a sample of wustite is $Fe_{0.93} O_{1.00}$. The percentage of iron in the form of $Fe^{3+}$ ion is nearly:

In dilute aqueous $H_2SO_4$,the complex diaquodioxalatoferrate$(II)$ is oxidized by $MnO_4^-$. For this reaction,the ratio of the rate of change of $[H^{+}]$ to the rate of change of $[MnO_4^-]$ is

Find the quantity of dihydrogen required to prepare $2 \ L$ ammonia gas from $1 \ L$ dinitrogen.

At $STP$,'$x$' $g$ of a metal hydrogen carbonate $(MHCO_3)$ (molar mass $84 \ g \ mol^{-1}$) on heating gives $CO_2$,which can completely react with $0.2 \ mol$ of $MOH$ (molar mass $40 \ g \ mol^{-1}$) to give $MHCO_3$. The value of '$x$' is