Linked from
The 8 pages that link to Lemon juice, each with the reason it gives.
MayonnaiseRelated: It can provide the acid component and a citrus flavor in mayonnaise.
VinaigretteRelated: It can replace vinegar as the acidic component of a vinaigrette.
HummusRelated: Its acidity brightens hummus and balances the chickpeas and tahini.
PaneerRelated: It is a common household acid for separating paneer curds from whey.
Cocktail sauceRelated: A squeeze brightens the sauce and offsets the sweetness of ketchup.