Syrup of lemon contains citric acid .When it reacts with sodium salicylate,salicylic acid is seperated as indiffusible precipitates.
The precription can be dispensed in two ways.Follow method B for precipitate yielding interaction or replace syrup of lemon with simple syrup and tincture of lemon.syrup of lemon is prescribed as a flavouring agent so its replacement with simple syrup and tincture of lemon will not effect the therapeutic value of the mixture