Browning of cut apple is due to the oxidation of polyphenols at a particular pH to quinones, which further undergoes polymerization to form brown coloured tannins.
This browning reaction can be prolonged or slowed down by using reducing agents or by changing the pH.
Applying lemon juice (i.e., citric acid) on the cut apple, lowers the pH at the surface of the apple. This prevents the oxidation reaction. Thus, browning of cut apple can be prolonged by applying lemon juice.
Cut apple turns brown when exposed to air because polyphenols are released.
These polyphenols undergo oxidation in the presence of air and impart brown colour.
Correct Answer - A
`(a)` If jack picks an apple in `.^(15)C_(1)` ways, then Jill in `.^(14)C_(1)^(10)C_(1)`.
If jack picks a pear in `.^(10)C_(1)` way, then Jill in `.^(15)C_(1)^(9)C_(1)`.
`:.` Total...