A student while trying to identify two gases labeled and , found that gas A is acidic to litmus paper and turn acidified potassium dichromate solution green, while gas B turns red litmus paper blue and forms dense white fume with hydrogen chloride. The correct identity of and respectively are ____________
A. and B. and C. and D. and
Correct Answer: B
Explanation
For A to be acidic to litmus, it is likely to be and both of which are acidic. Because A decolourizes (reduces) acidified potassium dichloromate, it must be a reducing agent, and so is and not forms dense white fume with hydrogen chloride. So, A and B respectively are \& .
