Question

Only exothermic reactions are spontaneous.

• A. True
• B. False

Answer 1

The correct option is B

False

So, we know the definition of spontaneous process.
$\Rightarrow$A process that can take place by itself under the given set of conditions one it has been initiated, if necessary, is said to be a spontaneous process.
Most of the exothermic reactions are spontaneous. The process which are accompanied by decrease of energy is generally spontaneous.
For example:- $C\left(s\right)+O_2\left(g\right)\to C{O}_2\left(g\right)$
But there are many reactions which are endothermic and spontaneous as well.
For example:- $HgO\left(s\right)\to Hg\left(l\right)+1/2O_2\left(g\right)$
So, you can see here that
$△$ H = -ve$\Rightarrow$ exothermic

$△$ H = +ve$\Rightarrow$ endothermic
$△$ H can be both -ve or +ve for a spontaneous process.