Question

Give a molecular formula of bleaching powder.

Answer 1

Hint: Substances that have more than one atoms or elements bonded together are called molecules. A chemical formula of a compound shows the symbol of elements present in that compound. It also shows the ratio of the elements to one another.

Complete step by step solution:
Bleaching powder is calcium hypochlorite. As the name suggests calcium hypochlorite will be formed of calcium and hypochlorite. We know the symbol of calcium is $Ca$ . Atomic number of calcium is $20$ . Its electronic configuration is$1{s^2}2{s^2}2{p^6}3{s^2}3{p^6}4{s^2}$. As it has two valence electrons so it will form two bonds. Hypochlorite is an anion which is made up of oxygen and chlorine. We know oxygens form double bonds as it has two valence electrons and chlorine forms a single bond this means in hypochlorite oxygen is attached to chlorine with a single bond and it is an anion so there will be a free electron (which will belong to oxygen). So it will be represented as $Cl{O^ - }$ . Since there is one free electron in hypochlorite ions, therefore two hypochlorite ions will be needed to form compounds. One calcium and two hypochlorite ions will together form bleaching powder. So the molecular formula will be $Ca{\left( {ClO} \right)_2}$.

Note: To solve such questions write the symbol of cation on the left side and write its charge just below it. Similarly write the symbol of anion on the right side and its charge below it. Charge on the anion will be equal to the number of atoms of cation and charge of cation will be equal to the number of atoms of anion. Combining all these things we will get the chemical formula of the desired compound. Also remember to reduce the molecules to the smallest integer.