When 1 mole of a substance `(X)` was treated with an excess of water, 2 moles of readily combustible gas were produced along with solution which when reacted with `CO_(2)` gas produced a white turbidity. The substance `(X)` could be

Options

A. `Ca`
B. `CaH_(2)`
C. `Ca(OH)_(2)`
D. `Ca(NO)_(2)`

Answer

B

Explanation

`underset(" 1 mole") (Ca) + 2 H_(2)O to Ca(OH)_(2) + underset("1 mole")(H_(2))`
`underset("1 mole")(CaH_(2)) + 2 H_(2) O to Ca(OH)_(2) + underset("2 moles")(2 H_(2))`
`Ca(OH)_(2) + CO_(2) underset(" White turbidity")(CaCO_(3)) + H_(2)O`
Since both Ca and `CaH_(2)` react with `H_(2)O` to produce combustible `H_(2)` gas but 1 mole of `CaH_(2)` produces two moles of `H_(2)` , therefore , option (b) is correct .