Chemistry · Chemical principles involved in the qualitative salt analysis Anions: CO3(2-), S2-, SO4(2-), NO3-, NO2-, Cl-, Br-, I- (Insoluble salts excluded)

A white solid imparts a violet colour to a Bunsen flame. On being heated with co

A white solid imparts a violet colour to a Bunsen flame. On being heated with concentrated \( \boldsymbol{H}_{2} \boldsymbol{S} \boldsymbol{O}_{4}, \) the solid gives violet vapours that turns starch paper blue. The salt may be :

  • A. Nal
  • B. KI
  • C. \( C a B r_{2} \)
  • D. \( M g I_{2} \)

Step-by-step solution

The violet flame indicates the presence of potassium (K+). Concentrated H2SO4 oxidizes iodide (I-) to iodine (I2), which forms violet vapors and turns starch paper blue. KI fits both observations.
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