Question

Choose the correct pair among the following in
which both elements show flame colouration in
Bunsen burner flame.
निम्नलिखित में से उस सही युग्म का चयन कीजिए जिसमें दोनों तत्व
बुन्सन बर्नर ज्वाला में ज्वाला को रंग प्रदान करते हैं?
Be, Ba
Ca, Ba
Mg, Be
Ba, Mg​

Answer 1

Option B, i.e., Calcium and Barium  impart a colored flame during the flame test

Explanation:

The molecular sizes of Be and Mg are small, and their electrons are very tightly bound. Thus, to extract these electrons from the structure, a very high amount of external energy is needed, which cannot be derived from a Bunsen burner. Hence, these elements do not yield any colored flame during the flame test.

Hence. all pairings containing these 2 elements have to be eliminated, i.e., Options A, C and D  

Barium and Calcium show a positive flame test since they impart a brick red and apple green colored flames, respectively, when they are subjected to the flame test.

Hence, the pairing which imparts a color to the flame is Option b, i.e., Ca and Ba