A test-tube containing $\text{HBr(g)}$ and another separate test-tube containing $\text{HI(g)}$ are heated until both reach the same temperature. Which set of observations could be seen?
- AHBr: a brown vapour appears; HI: no change
- BHBr: a purple vapour appears; HI: no change
- CHBr: no change; HI: a brown vapour appears
- DHBr: no change; HI: a purple vapour appears