(a)[5]
Describe the reactions of hydrochloric acid with: - calcium oxide - magnesium - a named acid-base indicator of your choice.
(b(i))[1]
What sort of chemical reaction is this?
(b(ii))[1]
Which one of the following pH values is the pH of an aqueous solution of sodium hydroxide? Circle the correct choice. pH 2 pH 5 pH 7 pH 13
(b(iii))[1]
State the name of the gas that is released.
(b(iv))[1]
Which one of the following statements about sodium hydroxide is correct? Tick one box. Pure sodium hydroxide melts across a temperature range. Impure sodium hydroxide has a sharp melting point. Pure sodium hydroxide boils between 319 ^{\circ}C and 1390 ^{\circ}C. Pure sodium hydroxide has a sharp boiling point.
(b(v))[1]
Why is it essential for the ingredients in medicines to be pure?