Clue: Content to leave alcohol, rising QC consumes a lime and soda? (7)
Answer: ALKALIS
Explanation: Definition: lime and soda?
A charade of AL ('content to leave **A**lcoho**L**') plus KALIS, an envelope ('consumes') of 'a' in KLIS, a reversal ('rising' in a down light) of SILK ('QC', informally). Excellent clue.