Q1
Mg : silvery white metal. (All grp 1 and 2 metals are generally silver in colour.)
HCl: colourless solution
Observations: Effervescence observed. Colourless gas is produced. When a lighted splint is brought close to the gas, it extinguishes with a pop sound.
From test above we deduce the gas produced is: Hydrogen gas.
The type of reaction is an acid-metal reaction
Balance eqn:
2Mg(s) + 2HCl(aq) -> 2MgCl (aq) + H2(g)
Q2
CuSo4(aq) appears as a blue aqueous solution.
NaoH appears as a colourless solution
Observations: the blue solution gradually turns colourless with a formation of a greenish blue solid.
The type of reaction is a double displacement reaction.
Balanced equation:
CuSO4(aq) + 2NaOH(aq) -> Cu(OH)2(aq) + Na2SO4(aq)