Question

Write the formula of the following salt:

Zinc Hydroxide

Answer 1

Chemical formula: The molecule of an element or a compound may be represented by symbols of the elements present in one molecule of the compound. It is known as a chemical formula.
Example: HCl is the formula of hydrogen chloride and NaCl is that of sodium chloride.

Significance of a Chemical Formula :

• It represents the name of various elements present in that substance.
• The chemical formula of a substance represents one molecule of that substance.
• The relative number of atoms of various elements present in one molecule of that element or compound.
• Relative masses of various elements in the compound.
• We can calculate the gram molecular mass of that substance.

Writing a Chemical Formula:

• Step-I: Write the symbol of the positive ion or the radical to the left and that of the negative ion or radical to the right.

$$\begin{gathered} \mathrm{Symbol}\mathrm{for}\mathrm{Zinc}\mathrm{is}\mathrm{Zn},\mathrm{and}\mathrm{the}\mathrm{charge}\mathrm{is}+2. \\ \mathrm{It}\mathrm{is}{\mathrm{Zn}}^{+2}\mathrm{ion} \\ \mathrm{Symbol}\mathrm{for}\mathrm{hydroxide}\mathrm{ion}\mathrm{is}{\mathrm{OH}}^{-1} \end{gathered}$$

• Step-II: Put the valency of each radical or the ion on its top right.
• Divide the valency by the highest common factor, if any, to get a simple ratio. Now ignore the (+) and (–) signs.
• Interchange the valency of radicals or ions.
• ${\mathrm{Zn}}^{+2}{\mathrm{OH}}^{-1}$
• Step-III: Shift the valency to the lower right side of the radical or ion. If the compound radical receives a number more than 1, enclose it within brackets.
• ${\left(\mathrm{Zn}\right)}_1{\left(\mathrm{OH}\right)}_2$
• Do not enclose simple radicals within brackets.
• The final answer for zinc hydroxide is $\mathrm{Zn}{\left(\mathrm{OH}\right)}_2$.

The formula of Zinc Hydroxide is $\mathrm{Zn}{\left(\mathrm{OH}\right)}_2$