Spot the mistake...
During a vacation, the Tan family was at an overseas chemistry laboratory. Mrs Tan wanted to get samples of solutions as souvenirs based on her children's favourite colours:
Benedict - green - iron (III) nitrate
Bob - blue - copper (II) sulfate
Brenda - red - iron (III) thiocyanate
Brian - orange - potassium dichromate
Billy - yellow - potassium chromate
However, Mr Tan pointed out that ONE of his children will NOT be happy with what they receive.
Benedict, Bob, Brenda, Brian or Billy?