Match Column-$I$ and Column-$II$ with the correct relation:

Column-$I$	Column-$II$
$(i)$ Ammonium phosphomolybdate	$(a)$ $(NH_4)_2MoO_4$
$(ii)$ Ammonium phosphate	$(b)$ $Mg^{2+} + NH_4OH$
$(iii)$ Mixture of magnesia	$(c)$ $H_3PO_4$
$(iv)$ Ammonium molybdate	$(d)$ $(NH_4)_3PO_4$
$(v)$ Phosphoric acid	$(e)$ $(NH_4)_3PO_4 \cdot 12MoO_3$

Assign $A$,$B$,$C$,$D$ from the given type of reaction.
$BaCrO_4 \downarrow + CH_3COOH \text{ (Excess)} \longrightarrow \text{No reaction}$

For the kinetic study of the reaction of iodide ion with $H_{2}O_{2}$ at room temperature, which of the following statements are correct?
$(A)$ Always use freshly prepared starch solution.
$(B)$ Always keep the concentration of sodium thiosulphate solution less than that of $KI$ solution.
$(C)$ Record the time immediately after the appearance of blue colour.
$(D)$ Record the time immediately before the appearance of blue colour.
$(E)$ Always keep the concentration of sodium thiosulphate solution more than that of $KI$ solution.
Choose the correct answer from the options given below:

Given below are two statements:
Statement $I$: Sodium dichromate and potassium dichromate are classified as primary standards in titrimetric analysis.
Statement $II$: Phenolphthalein is a weak base,therefore it dissociates in acidic medium.

Match List-$I$ with List-$II$.

List-$I$ (Complex)	List-$II$ (Colour)
$A$. $Mg(NH_4)PO_4$	$I$. Brown
$B$. $K_3[Co(NO_2)_6]$	$II$. White
$C$. $MnO(OH)_2$	$III$. Yellow
$D$. $Fe_4[Fe(CN)_6]_3$	$IV$. Blue

Choose the correct answer from the options given below:

Prolonged heating is avoided during the preparation of ferrous ammonium sulphate to: