The weight of sodium carbonate required to prepare $500 \ mL$ of a semi-normal solution is .......... $g$.

How many grams of $3-$hydroxypropanal $(MW=74)$ must be dehydrated to produce $7.8 \ g$ of acrolein $(MW=56)$ $(C_3H_4O)$ if the percentage yield is $64\%$? (Round off to the nearest integer).
[Given: Atomic masses: $C = 12.0 \ u, H = 1.0 \ u, O = 16.0 \ u$]

$LiOH$ reacts with $CO_2$ to form $Li_2CO_3$ (atomic mass of $Li = 7$). The amount of $CO_2$ (in $g$) consumed by $1\, g$ of $LiOH$ is closest to $....\, g$

When $100 \, mL$ of $1 \, N \, NaOH$ solution and $10 \, mL$ of $10 \, N$ sulphuric acid solution are mixed together,the resulting solution will be:

The ratio of amounts of $H_2S$ needed to precipitate all the metal ions from $100 \ mL$ of $1 \ M$ $AgNO_3$ and $100 \ mL$ of $1 \ M$ $CuSO_4$ is

$A$ given initial mass of $KClO_3$ on $50\%$ decomposition produces $67.2 \ L$ of oxygen gas at $0 \ ^\circ C$ and $1 \ atm$. The other product of decomposition is $KCl$. The initial mass of $KClO_3$ (in $g$) taken is: