In the preparation of baking soda,what is the ratio of $H_2O$ and $CO_2$ used to react with $Na_2CO_3$ to form $NaHCO_3$?

Moles of conc. $HNO_3$ required to oxidise one mole of sulphur is :
$S + 6HNO_3 \rightarrow H_2SO_4 + 6NO_2 + 2H_2O$

$0.5 \ mol$ of $H_2SO_4$ is mixed with $0.2 \ mol$ of $Ca(OH)_2$. What is the maximum number of moles of $CaSO_4$ formed?

In Ostwald's process for the manufacture of nitric acid,the first step involves the oxidation of ammonia gas by oxygen gas to give nitric oxide gas and steam. What is the maximum weight of nitric oxide that can be obtained starting only with $10.00 \ g$ of ammonia and $20.00 \ g$ of oxygen?

In the Haber process,$30 \ L$ of dihydrogen and $30 \ L$ of dinitrogen were taken for the reaction,which yielded only $50\%$ of the expected product. What will be the composition of the gaseous mixture under the aforesaid condition in the end?

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