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

$20 \ mL$ of $0.1 \ M$ $HCl$ is added to $30 \ mL$ of $0.1 \ M$ $NaOH$. To this solution,an extra $50 \ mL$ of water was added. What is the molarity of the final solution formed (in $M$)?

The set of numerical coefficients that balances the equation $K_2CrO_4 + HCl \to K_2Cr_2O_7 + KCl + H_2O$ is

$A$ closed $10 \, L$ vessel contains $1 \, L$ water gas $(1:1 \, CO : H_2)$ and $9 \, L$ air ($20 \% \, O_2$ by volume) at $STP$. The contents of the vessel are ignited. The number of moles of $CO_2$ in the vessel is closest to $.... \, mol$.

When copper is reacted with a certain concentration of nitric acid,nitric oxide and nitrogen dioxide are produced in equal volumes according to the following reaction:
$xCu + yHNO_3 \to xCu(NO_3)_2 + NO + NO_2 + 3H_2O$
What are the stoichiometric coefficients $x$ and $y$?

$100 \ mL$ of $0.2 \ M \ H_2SO_4$ is added to $100 \ mL$ of $0.2 \ M \ NaOH$. The resulting solution will be