Question

A white solid imparts a violet colour to a Bunsen flame. On being heated with concentrated `H_(2)SO_(4)`, the solid gives violet vapours that turn starch paper blue. The salt may be :
A. KI
B. NaI
C. `MgI_(2)`
D. `CaBr_(2)`

Answer 1

Correct Answer - A
`K to` violet colour in flame test
`2I^(-) + conc. H_(2)SO_(4) to HI + SO_(4)^(2-) , HI+ H_(2)SO_(4) to I_(2) +H_(2)O+SO_(2)`
`I_(2) + "starch" to " blue colour"`