Which of the following statements is not true about Mohr's salt?

$FeSO_4 \cdot (NH_4)_2SO_4 \cdot 6H_2O$ is called:

The reagent commonly used to determine the hardness of water titrimetrically is

The primary standard solution for the estimation of $Na_2S_2O_3$ is:

The volume of $\frac{N}{10}$ $NaOH$ required to neutralize $100 \ mL$ of $\frac{N}{25}$ $HCl$ is......$mL$

$2.52 \ g$ of oxalic acid dihydrate was dissolved in $100 \ mL$ of water. $10 \ mL$ of this solution was diluted to $500 \ mL$. The normality of the final solution (in $N$) and the amount of oxalic acid (in $mg/mL$) in the solution are respectively