Answer: The percent yield of this combination reaction is 41.3 %
Explanation : Given,
Mass of
= 5.0 g
Mass of
= 10.0 g
Molar mass of
= 23 g/mol
Molar mass of
= 71 g/mol
First we have to calculate the moles of
and
.


and,


Now we have to calculate the limiting and excess reagent.
The balanced chemical equation will be:

From the balanced reaction we conclude that
As, 2 mole of
react with 1 mole of 
So, 0.217 moles of
react with
moles of 
From this we conclude that,
is an excess reagent because the given moles are greater than the required moles and
is a limiting reagent and it limits the formation of product.
Now we have to calculate the moles of 
From the reaction, we conclude that
As, 2 mole of
react to give 2 mole of 
So, 0.217 mole of
react to give 0.217 mole of 
Now we have to calculate the mass of 

Molar mass of
= 58.5 g/mole

Now we have to calculate the percent yield of this reaction.
Percent yield = 
Actual yield = 5.24 g
Theoretical yield = 12.7 g
Percent yield = 
Percent yield = 41.3 %
Therefore, the percent yield of this combination reaction is 41.3 %