The action of steam on heated iron is represented as:

Which of the following equations is written incorrectly?

The number of moles of $H_2$ required to produce $10$ moles of $NH_3$ in the following reaction is:
$a H_{2(g)} + b NO_{2(g)} \longrightarrow c NH_{3(g)} + d H_2O_{(g)}$

$100 \ mL$ of $0.05 \ M$ $Cu^{2+}$ aqueous solution is added to $1 \ L$ of $0.1 \ M$ $KI$ solution. The number of moles of $I_2$ and $Cu_2I_2$ formed are respectively:

Calcium carbonate reacts with aqueous $HCl$ to give $CaCl_2$ and $CO_2$ according to the reaction given below: $CaCO_{3(s)} + 2HCl_{(aq)} \to CaCl_{2(aq)} + CO_{2(g)} + H_2O_{(l)}$
What mass of $CaCl_2$ will be formed when $250 \ mL$ of $0.76 \ M$ $HCl$ reacts with $1000 \ g$ of $CaCO_3$? Name the limiting reagent. Calculate the number of moles of $CaCl_2$ formed in the reaction.

Butane reacts with oxygen to produce carbon dioxide and water following the equation given below: $C_4H_{10(g)} + \frac{13}{2} O_{2(g)} \rightarrow 4 CO_{2(g)} + 5 H_2O_{(l)}$. If $174.0 \ kg$ of butane is mixed with $320.0 \ kg$ of $O_2$,the volume of water formed in litres is $...........$ (Nearest integer). [$Given$: $(a)$ Molar mass of $C, H, O$ are $12, 1, 16 \ g \ mol^{-1}$ respectively,$(b)$ Density of water $= 1 \ g \ mL^{-1}$]