Q$3($a$)$ Give reason$($s$)$ for the following:

$6$ degree

Using Nafion as a binder in the catalyst layer?

Although increasing the cell temperature is good for PEMFC performance, the optimum operating cell temperature is limited to $80C?$

What is the amount of hydrogen and oxygen $($in moles$)$ consumed in a $1-kW$ fuel cell operating for $10$ hours, at a cell voltage of $0\mathrm{.}7V?$