If isobutane and $n$-butane are present in a gas,then how much oxygen should be required for the complete combustion of $5 \ kg$ of this gas?

Match the following List-$I$ and List-$II$ at $STP$:

List-$I$	List-$II$
$A. 10 \ g \ CaCO_3 \xrightarrow{\Delta} \text{decomposition}$	$1. 0.224 \ L \ CO_2$
$B. 1.06 \ g \ Na_2CO_3 \xrightarrow{\text{Excess } HCl} \text{reaction}$	$2. 4.48 \ L \ CO_2$
$C. 2.4 \ g \ C \xrightarrow{\text{Excess } O_2} \text{combustion}$	$3. 0.448 \ L \ CO_2$
$D. 0.56 \ g \ CO \xrightarrow{\text{Excess } O_2} \text{combustion}$	$4. 2.24 \ L \ CO_2$
	$5. 22.4 \ L \ CO_2$

$100 \ mL$ of $PH_3$ when completely decomposed produces phosphorus and hydrogen. The change in volume of the gas is
$PH_{3(g)} \longrightarrow P_{(s)} + \frac{3}{2} H_{2(g)}$

$20 \ mL$ 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 conversion of oxygen to ozone occurs to the extent of $15\%$ only. The mass of ozone that can be prepared from $67.2 \ L$ of oxygen at $1 \ atm$ and $273 \ K$ will be ............ $g$.

$4.0 \ g$ of a mixture containing $Na_2CO_3$ and $NaHCO_3$ is heated to $673 \ K$. The loss in mass of the mixture is found to be $0.62 \ g$. The percentage of sodium carbonate in the mixture is: