For number 22. The answer is c. To find this look at the numbers before each compound O2 has no number which means 1, while CO2 has a 2 in front
<span>The answer is Gaseous metals</span>
PH indicators detect the presence of H+ and OH-. They do this by reacting with H+ and OH-: they are themselves weak acids and bases. If an indicator is a weak acid and is coloured and its conjugate base has a different colour, deprotonation causes a colour change.
