Upon mixing equal volumes of aqueous solutions of $0.1 \, M \, HCl$ and $0.2 \, M \, H_2SO_4$,the concentration of $H^{+}$ in the resulting solution is $.... \, mol / L$.

$25 \, mL$ of a decinormal $NaOH$ solution is completely neutralized by $0.16 \, g$ of a dibasic acid. The molecular weight of the dibasic acid is:

In what ratio by mass carbon dioxide $(CO_2)$ and nitrogen $(N_2)$ should be mixed so that the partial pressure exerted by each gas is the same?

$0.1 \text{ mole}$ of potassium permanganate was heated at $300^{\circ}C$. What is the weight (in $g$) of the residue? ($Mn = 55 \text{ u}$,$K = 39 \text{ u}$,$O = 16 \text{ u}$)

Normality of $2 \, M$ sulphuric acid is

$A$ cylinder of cooking gas in a household contains $11.6 \, kg$ of butane. The thermochemical reaction for the combustion of butane is,
$2 C_4H_{10(g)} + 13 O_{2(g)} \longrightarrow 8 CO_{2(g)} + 10 H_2O_{(l)}$
$\Delta H = -2658 \, kJ/mol$
If the household needs $15000 \, kJ$ of energy per day,the cooking gas cylinder will last for about $...... \, days$.