Question

Assertion:
The evolution of any colourless gas confirms the gas to be chlorine
Reason:
 \[C{l_2}\] and \[N{O_2}\] are not colourless.
A.Both Assertion and Reason are correct and the Reason is the correct explanation for assertion
B.Both assertion and reason are correct but the reason is not the correct explanation for assertion.
C.Assertion is correct but reason is incorrect
D.Assertion is incorrect but reason is correct

Answer 1

Hint:During the course or upon completion of many chemical reactions, gases are released. The nature of these gases is often determined first-hand by the smell or the colour of the gas.

Complete step by step answer:
There are quite a few reactions wherein various gases are evolved. Many times these gases may or may not have a smell but are colourless. There is a possibility that these colourless gases often go unnoticed in experiments, until and unless we have a detection mechanism for them. Hence the assertion that the evolution of any colourless gas confirms the gas to be chlorine is incorrect because several gases exhibit the property being colourless. One such example of a colourless gas can be Hydrogen.
Also, Chlorine gas is found to be yellowish - green in colour. The colour of Chlorine is influenced by the conditions under which it is observed. If observed only in sunlight, one might see the gas to be only greenish in colour. But if chlorine is observed in a heated environment, then it may be viewed as a yellowish gas. And \[N{O_2}\] gas is brownish in colour. Hence the reason that \[C{l_2}\] and \[N{O_2}\] are not colourless is correct.
Therefore, we can say that:
Assertion is incorrect but reason is correct.

Hence, Option D is the correct option.

Note:
Now colourlessness is a property that is exhibited by various gases including hydrogen, Carbon dioxide and oxygen, along with several others.