Hydrogen Question 14
A sample of potassium bromide is treated with perchloric acid solution. The reaction mixture is cooled and solid
potassium chlorate is removed by filtering, then dried and weighed It weighed exactly 8.89​

the only liquid elements at standard temperature and pressure are bromine (br) and mercury (hg). although, elements caesium (cs), rubidium (rb), francium (fr) and gallium (ga) become liquid at or just above room temperature.

explanation:

every chemical equation adheres to the law of conservation of mass, which states that matter cannot be created or destroyed. therefore, there must be the same number of atoms of each element on each side of a chemical equation.

i think it's letter a.