If you spill a chemical toilet cleaning liquid on your hand, your first aid would be:
Aqueous NaHCO3
Solution: Option (B)
Option A: Aqueous ammonia cannot be used for this purpose as mixing aqueous ammonia with toilet cleaning liquid will lead to the formation of a toxic gas called chloramine which can hurt the lungs and even be deadly in higher concentrations.
Option C: Aqueous NaOH cannot be used for this purpose because it is corrosive in nature to the skin.
Option D: Vinegar cannot be used for this purpose as it is acidic in nature and cannot neutralise the effect of toilet cleaning liquid.
So, the correct answer is Option B.