Question

Which of the following is not correct?
A) Ammonia is used as a refrigerant
B) A mixture of $CaNCN$and $C$ is known as nitrolim
C) A mixture of $Ca{({H_2}P{O_4})_2}$ and $CaS{O_4}.2{H_2}O$ is known as superphosphate of lime.
D) Hydrolysis of $NC{l_3}$ gives $N{H_3}$ and $HOCl$

Answer 1

Here our duty is to find the incorrect one among the four options. This can be achieved only by analyzing and examining each of the options. We have to take out all the options one by one and check the properties each in given as like whether ammonia is used a reagent or not , correct mixture of nitrolim , mixture included in superphosphate of lime and hydrolysis of $NC{l_3}$.

Complete step-by-step answer:
First of all we should check each of the answers one by one.
Let us look onto the first option which is stating that ammonia is used as a refrigerant.
We have to know that ammonia is stored as a liquid in refrigeration systems in closed containers under pressure. Here, when the pressure is released liquid will evaporate and form invisible vapours . As a result ammonia is used as a refrigerant. Therefore, option A is the correct answer.

Next we shall look onto the second option which is stating about mixture of nitrolim.
Let us look onto the formation of a mixture of nitrolim.
${N_2} + {O_2} + Ca{C_2} \to CaC{N_2} + CO$
Here we can see calcium carbide on reaction with air at ${1000^ \circ }C$ gives nitrolim which is a mixture of $CaC{N_2}$ and carbon monoxide. But as per option it is given as $C$ instead of carbon monoxide which is incorrect as in case of nitrolim. Therefore, option B is incorrect.

We should check remaining options too as it is also having a chance of being incorrect. Third option is stating about the mixture of superphosphate lime. Actually we have to know that superphosphate lime is a mixture of gypsum which is calcium sulphate and monobasic calcium phosphate. It is the same as given in the option. Therefore option C is the correct one.

Finally we have to look at the last option which is stating about hydrolysis of $NC{l_3}$. Here we need to keep in mind that hydrolysis of $NC{l_3}$ results in the formation of ammonia gas and hydrogen chlorate. So it proves to be the right one as same as given in options.

Hence , proved that option B is the incorrect option.

Note: The only solution to find the incorrect answer is to have a basic idea about some particular reactions as given in the options. If we have those facts in mind, it will help us to find out the answer quickly. We have to know that nitrolim is otherwise called calcium cyanamide. Here we have a chance of misunderstanding carbon as carbon monoxide since they are relatable compounds which will result in determining the option to be correct. So, we should carefully deal with options in such kinds of questions.