What is formed when an acid reacts with a base?

Which of the following statements is not correct?

Which of the following is used for the dissolution of gold?

What effect does an increase in the concentration of $H^{+}(aq)$ in a solution have on the $pH$ of the solution?

In a basic aqueous solution,how does the basicity of the solution change as the concentration of $[OH^{-}]$ ions decreases?

When soap is scrubbed on a stain of curry on a white cloth,why does it become reddish-brown,and why does it turn yellow again when the cloth is washed with plenty of water?