Give balanced equations for the following conversions:

(a) An alkene to an alkane

(b) An alkene to an alcohol

(c) An alkyne to an alkene.

(a) An alkene to an alkane

$\underset{\text{ethene}}{\text{C}$2\text{H}4} + \text{H}2 \xrightarrow[300\degree\text{C}]{\text{Nickle}} \underset{\text{ethane}}{\text{C}2\text{H}_6}

(b) An alkene to an alcohol

$\underset{\text{ ethene}}{\text{C}$2\text{H}4} + \text{H}2\text{O} \xrightarrow[300\degree\text{C, 60 atm.}]{\text{H}3\text{PO}4} \underset{\text{ethene}}{\text{C}2\text{H}_5\text{OH}}

(c) An alkyne to an alkene.

$\underset{\text{ ethyne [acetylene]}}{\text{H}$2\text{C}2} + \text{H}2 \xrightarrow[300\degree\text{C}]{\text{Nickle}} \underset{\text{ethene}}{\text{C}2\text{H}_4}