Depends on the plant. You can determine whether acidic or alkaline liquids are better for a specific seed by placing the same number of seeds in water, vinegar and club soda and watch them germinate. For more accuracy you can scale it like:
100% club soda
75% club soda 25% water
50% club soda 50% water
25% club soda 75% water
100% water
25% vinegar 75% water
50% vinegar 50% water
75% vinegar 25% water
100% vinegar