In a chemical reaction, the sum of the formula weights of all reactants is $274 \text{ u}$ and the atom economy is $50\%$. Calculate the formula weight of the desired product. (in $\text{ u}$)

Molarity of a solution containing $1 \ g$ $NaOH$ in $250 \ mL$ of solution is ...... $M$.

What volume of $0.8 \ M$ solution contains $0.1 \ mole$ of the solute? (in $mL$)

White phosphorus reacts with chlorine and the product hydrolyses in the presence of water. Calculate the mass of $HCl$ obtained by the hydrolysis of the product formed by the reaction of $62 \ g$ of white phosphorus with chlorine in the presence of water.

$4.4 \ g$ of a gas at $STP$ occupies a volume of $2.24 \ L$. The gas can be:

Hydrogen gas is prepared in the laboratory by reacting dilute $HCl$ with granulated zinc. The following reaction takes place: $Zn + 2HCl \to ZnCl_2 + H_2$. Calculate the volume of hydrogen gas liberated at $STP$ when $32.65 \ g$ of zinc reacts with $HCl$. ($1 \ mol$ of a gas occupies $22.7 \ L$ volume at $STP$; atomic mass of $Zn = 65.3 \ u$).