<u>Answer:</u> The coefficient of NOCl in the given balanced chemical equation is 1
<u>Explanation:</u>
A balanced chemical equation is defined as the equation in which total number of individual atoms on the reactant side is equal to the total number of individual atoms on product side.
Law of conservation of mass states that mass can neither be created nor be destroyed but it can only be transformed from one form to another form.
Every balanced chemical equation follows law of conservation of mass
For the given balanced chemical equation:

By Stroichiometry of the reaction:
1 mole of nitrogen monoxide gas reacts with
moles of chlorine gas to produce 1 mole of NOCl
Hence, the coefficient of NOCl in the given balanced chemical equation is 1