A colourless solution is tested by the following reactions. Which reaction is not characteristic of an acid?
A
A piece of magnesium ribbon is added. Bubbles are seen and the magnesium disappears.
B A pungent smelling gas is produced when ammonium carbonate is added.
C Copper oxide powder is added and the mixed is warmed. The solution turns blue.
D
The solution turns blue litmus red.

Sandy is building a small toy car. he wants to use a balloon to power the toy car. he fills a balloon with air and then attaches a straw to the balloon. he tapes the balloon-straw combination to the car and then releases the end of the balloon. the toy moves forward as the air from the balloon comes out the back of the straw. what can sandy do to make the toy car move faster? a) use less air in the balloon. b) blow up the balloon more. c) use a longer straw. d) use larger tires.