Reaction forming inseparable product Z

Steps:

• The complete reaction on heating forms new substance Z from elements X and Y.
• Inseparability of Z from X and Y implies chemical bonding where components cannot be recovered by physical means.
• Statement 1 holds because such stable, inseparable products form when a metal (X) combines with non-metal Y, like in ionic compounds.
• Statements 2 and 3 fail as Z could be an alloy (mixture) if both metallic, lacking fixed composition or compound nature.

Why B is correct:

• Tied to basic chemistry definition: Non-metal Y ensures chemical reaction yields inseparable compound, unlike metal-metal mixing.

Why the others are wrong:

• A: Includes 3, but no evidence for XY ratio; stoichiometry varies.
• C: Includes 2 and 3, but 2 overlooks possible mixtures; 3 assumes fixed formula.
• D: 2 alone ignores that Z need not be a compound without non-metal involvement.

Final answer: B