Grignard reagent RMgBr reacts with water to produce gas Q.
One gram of Q occupies 1.4 L at STP.
Moles of Q = 1.4/22.4 = 0.0625 mol, so molar mass = 1/0.0625 = 16 g/mol, identifying Q as CH₄.
Thus P = CH₃MgBr.
When P reacts with dry ice: CH3MgBr+CO2→CH3COOMgBr.
Upon treatment with H₃O⁺, this gives Z = CH₃COOH (acetic acid).
Molar mass of Z = 60 g/mol.
Mass of 0.1 mol = 0.1 × 60 = 6 g.