2023 · Q71
Which one of the following is the correct order of pH for the given substances?
General KnowledgeChemistry
- ACoffee < Lemon juice < Milk of magnesia < Blood
- BMilk of magnesia < Blood < Coffee < Lemon juice
- CLemon juice < Blood < Coffee < Milk of magnesia
- DLemon juice < Coffee < Blood < Milk of magnesia
Explanation
In order of increasing pH: lemon juice is strongly acidic (pH ~2), coffee is mildly acidic (pH ~5), human blood is slightly alkaline (pH ~7.4), and milk of magnesia (magnesium hydroxide suspension) is strongly alkaline (pH ~10.5). The correct ascending order is therefore Lemon juice < Coffee < Blood < Milk of magnesia.