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

Suppose a cooking gas cylinder contains $11.2 \, kg$ of isobutane. The thermochemical equation for the combustion of butane is given below:
$C_4H_{10}(g) + \frac{13}{2} O_2(g) \to 4CO_2(g) + 5H_2O(\ell); \Delta H = -2658 \, kJ$
If a family requires $15000 \, kJ$ of energy per day for cooking,how many days will the cylinder last?

If the reduction of a sample of $Cu_2O$ yields $1.27 \, g$ of $Cu$,then how many grams of oxygen must be present in it?

The volume of $2 \ N \ H_2SO_4$ solution is $0.1 \ dm^3$. The volume of its decinormal solution (in $dm^3$) will be

Normality of $2 \, M$ sulphuric acid is

When $500 \ mL$ of a gaseous hydrocarbon is burned in excess of $O_2$,it produces $2.5 \ L$ of $CO_2$ and $3.0 \ L$ of water vapor. What is the molecular formula of the hydrocarbon?