Consider the following reaction:
$3 PbCl_2 + 2 (NH_4)_3 PO_4 \rightarrow Pb_3(PO_4)_2 + 6 NH_4 Cl$
If $72 \ mmol$ of $PbCl_2$ is mixed with $50 \ mmol$ of $(NH_4)_3 PO_4$,then the amount of $Pb_3(PO_4)_2$ formed is $......... \ mmol$. (nearest integer)

$108 \ g \ Al$ and $213 \ g \ MnO$ were heated to initiate the reaction:
$2 Al + 3 MnO \to Al_2O_3 + 3 Mn$
Which of the following is correct? (Atomic weights: $Mn = 55$,$Al = 27$)

If $30 \, mL$ of $H_2$ and $20 \, mL$ of $O_2$ react to form water,what remains at the end?

Combustion of $50 \ mL$ methane is carried out with $150 \ mL$ of air containing $21 \%$ oxygen by volume. What will be the total volume of the gaseous mixture after the reaction? (Assume water is in the gaseous state and air contains $79 \%$ nitrogen by volume).
$CH_{4(g)} + 2O_{2(g)} \to CO_{2(g)} + 2H_2O_{(g)}$

How many moles of $PbCl_2$ will be obtained from the reaction between $6.5 \ g$ of $PbO$ and $3.2 \ g$ of $HCl$?

What is the maximum amount of $Cl_2$ gas produced when $1 \, g$ of $HCl$ and $1 \, g$ of $MnO_2$ are heated together (in $, g$)?