A mixture of salts `(Na_(2)SO_(3)+K_(2)Cr_(2)O_(7))` in a test tube is treated with dil. `H_(2)SO_(4)` and resulting gas is passed through lime-water. Which of the following observations is correct about this test

Options

A. Solution in test tube becomes green and lime water turns milky
B. Solution is test tube is colourless and lime water turns milky.
C. Solution in test tube becomes green and lime water remains clear
D. Solution in test tube remains clear and lime water also remains clear.

Explanation

`Na_(2)SO_(3)` reacts with dilute `H_(2)SO_(4)` to give `SO_(2)` gas which reacts with `K_(2)Cr_(2)O_(7) +` dil`H_(2)SO_(4)` to give a green solution due to the formation of `Cr_(2)(SO_(4))_(3)`. As whole of `SO_(2)` gas reacts away , on passing the resulting gas through lime water, it remains clear.