Which reaction is used for the preparation of $\alpha$-bromoacetic acid?

Give the reactions of benzoic acid $(C_6H_5COOH)$ with the following:
$(i)$ Sodium metal
$(ii)$ Solution of sodium hydroxide $(NaOH)$
$(iii)$ Solution of sodium bicarbonate $(NaHCO_3)$
$(iv)$ $P_2O_5$ or conc. $H_2SO_4$ $+$ heat
$(v)$ $PCl_5$
$(vi)$ $PCl_3$
$(vii)$ $SOCl_2$
$(viii)$ $NH_3$ $+$ high temperature
$(ix)$ $LiAlH_4$ / ether or $B_2H_6$
$(x)$ Sodalime $(NaOH + CaO)$ $+$ heat
$(xi)$ Conc. $HNO_3$ $+$ conc. $H_2SO_4$ $+$ heat
$(xii)$ $Br_2 + FeBr_3$
$(xiii)$ Oleum $(H_2SO_4 + SO_3)$ $+$ heat

Which one is the strongest acid?

Arrange the following compounds in the correct decreasing order of their acidic strength:
$(I) HCOOH$
$(II) CH_3COOH$
$(III) CH_3CH_2COOH$
$(IV) C_6H_5COOH$

Carboxylic acids are easily ionised. What is the main reason for this statement?

Which of the following does not give a silver mirror test with ammoniacal $AgNO_3$ solution?