The reaction of Grignard reagent with water yields an alkane:
RMgI+H2O→RH+Mg(OH)I
Given that 1 g of the gas RH occupies 1.4 dm3 at STP, we can find its molar mass. Using the standard molar volume at STP (22.4 dm3):
Molar mass of RH=1.4 dm3 g−122.4 dm3 mol−1=16 g mol−1
The alkane with a molar mass of 16 g mol−1 is methane (CH4).
Methane reacts with iodine in the presence of an oxidizing agent like HIO3 (which prevents the backward reaction by consuming the formed HI) to give methyl iodide:
CH4+I2HIO3CH3I+HI
Thus, compound (X) is methyl iodide (CH3I).
Compound (X) undergoes the Wurtz reaction when treated with sodium and dry ether to form a higher alkane:
2CH3I+2Nadry etherCH3−CH3+2NaI
Compound (Y) is ethane (C2H6).
The molar mass of ethane (C2H6) is:
2×12+6×1=30 g mol−1
Answer: 30