Choose the correct word.

1 Plastic chopping / slicing boards are easier to clean and more hygienic than wooden ones.
2 My mum used to give us a plate / mug of sandwiches and soft boiled eggs for breakfast every Sunday.
3 Sorry, I added too much lemon juice, so the smoothie is a little bit bitter / sour.
4 We found the service / tips in the restaurant to be extremely professional.
5 My doctor told me to stick to a balanced / balance diet and to exercise at least twice a week.