Question

QUESTION 7 What are the correct coefficients (reading from left to right) when the chemical equation is balanced? O 1, 3, 1, 3 O 3, 6, 1, 9 O1, 3, 2,1

Answer 1

Ans: 1,3,1,3

1) Balance the P atoms : left side one P atom and right side one P atom => so coeffieicents will be 1 each.

2) Balance the Cl atoms : Left side 3 Chlorine atoms as we fixed coefficent from PCl3 as 1. and to maintain right side also 3 Cl atoms we are giving 3 as coefficient for HCl

3) P and Cl atoms are balanced. Now, we go for O atoms balance : Right side we have 3 atoms of O ( as coefficient of H3PO3 is 1) ==> so to maintain 3 O atoms on left side also we are giving coefficient of H2O as 3.

4) And finally we are checking for hydrogen atoms wether they are balanced or not. : Yes, they are also balanced ( 6 hydrogens on both the sides)

Note: Always balance Oxygen and Hydrogen atoms as last steps for any equation.

Therefore, given equation is balanced with coefficients 1,3.1,3. i.e., Option B

Balanced equation is , PCl3 (l) + 3 H2O (l) -------> H3PO3 (aq) + 3 HCl (aq)