The weight of $H_2C_2O_4 \cdot 2H_2O$ required to prepare $500 \ mL$ of $0.2 \ N$ solution is .......... $g$.

Haemoglobin contains $0.33\%$ of iron by weight. The molecular weight of haemoglobin is approximately $67200$. The number of iron atoms (At. wt. of $Fe = 56$) present in one molecule of haemoglobin is

How many moles of potassium chlorate need to be heated to produce $5.6 \, L$ of oxygen at $STP$?

The molarity of a $NaOH$ solution prepared by dissolving $4 \ g$ of it in $250 \ mL$ of water is: (in $M$)

$A$ $20 \ mL$ solution of $KMnO_4$ with a concentration of $1 \ N$ reacts with $20 \ mL$ of oxalic acid. The weight of oxalic acid in the $1 \ N$ solution is ......... $g$.

Find the mass of potassium chlorate required to liberate $5.6 \ dm^3$ of oxygen gas at $STP$. (Molar mass of $KClO_3 = 122.5 \ g/mol$) (in $g$)