Which of the following is a weak acid?

Name the acid present in ant sting and give its chemical formula. Also,suggest a common method to get relief from the discomfort caused by the ant sting.

Which of the following salts has a $pH$ less than $7$? Why?

What is correct for an acidic aqueous solution?

What range of $pH$ is considered perfect for a fertile land?

What happens when a solution of an acid is mixed with a solution of a base in a test tube?
$(i)$ The temperature of the solution increases
$(ii)$ The temperature of the solution decreases
$(iii)$ The temperature of the solution remains the same
$(iv)$ Salt formation takes place