Question

One mole of calcium phosphide on reaction with excess of water gives

• A. One mole of phosphine
• B. Two moles of phosphoric acid
• C. Two moles of phosphine
• D. One mole of phosphorous pentoxide

Answer 1

The correct option is C Two moles of phosphine

The balanced equation for the reaction between calcium phosphide($C{a}_3{P}_2$) and excess water($H_{2}O$) to form phosphine($P{H}_3$) can be written as:
$C{a}_3{P}_2+6H_{2}O\to 3Ca(OH{)}_2+2P{H}_3$
Therefore 1 mole of calcium phosphide will form 2 moles of phosphine.