Which of the following gives the correct increasing order to acidic strength?

Calcium phosphate is present in tooth enamel. Its nature is:

A sample of soil is mixed with water and allowed to settle. The clear supernatant solution turns the pH paper yellowish-orange. Which of the following would change the colour of this pH paper to greenish-blue?

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

Write true or false for the following statements:

The separation of H⁺ ion from HCl molecules can occur in the absence of water.