Answer:
The correct formula for boron tribromide is BBr3 (option b).
In this compound, boron (B) has a valency of 3, and bromine (Br) has a valency of 1. The subscript 3 indicates that there are three bromine atoms bonded to one boron atom.
To determine the correct formula, it's important to understand the valencies of the elements involved. Boron typically has a valency of 3, which means it can form three bonds with other elements. Bromine, on the other hand, has a valency of 1, indicating that it can form one bond.
In boron tribromide, the three bromine atoms each form a single bond with the boron atom. So, the formula is BBr3, indicating one boron atom and three bromine atoms.
It's important to pay attention to the subscripts in a chemical formula, as they indicate the number of atoms present in the compound. In this case, the subscript 3 indicates that there are three bromine atoms bonded to one boron atom. If the formula were written as B3Br or 3BBr, it would imply that there are three boron atoms, which is incorrect.
Remember, when writing chemical formulas, it's crucial to consider the valencies and the number of atoms involved to accurately represent the compound.