The vapour density of a gas is $11.2$. The volume occupied by $11.2 \ g$ of this gas at $N.T.P.$ is ................ $L$

$20 \ mL$ of sodium iodide solution gave $4.74 \ g$ silver iodide when treated with excess of silver nitrate solution. The molarity of the sodium iodide solution is $........ M$. $(Nearest \ Integer \ value)$
$(Given: Na=23, I=127, Ag=108, N=14, O=16 \ g \ mol^{-1})$

The heat of combustion of ethylene $C_2H_{4(g)}$ is $-1420 \, kJ/mol$. The number of litres of $C_2H_4$ at $NTP$ that would evolve $355 \, kJ$ on combustion 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 $...... \, days$.

What volume of decimolar solution should be mixed in a solution of the same solute $(0.5 \, M, \, 200 \, mL)$ to make it $0.25 \, M$?

The ratio of the molar amounts of $H_2S$ needed to precipitate the metal ions from $20 \ mL$ each of $1 \ M \ Cd(NO_3)_2$ and $0.5 \ M \ CuSO_4$ is