CBSE Class 10 Answered

Hit and Trial Method

In this method of balancing chemical equations, trials are made to balance the equation by using the smallest whole number coefficient. Hence, this method is called the hit and trial method.

(i)  Count the number of times an element occurs on both sides.

(ii) An element with the least frequency of occurrence is balanced first.

(iii) When two or more elements have same frequency, metallic elements are balanced first.

Answer:

1] 3 MnO₂ + 2 Al → 3 Mn + 2 AlO₃

2] Cu + 2 AgNO₃ →  Cu(NO₃)₂ + 2 Ag

3] Fe₂O₃ + 3 CO → 2 Fe + 3 CO₂

4] MnO₂ + 4 HCl → MnCl₂ + 2 H₂O + Cl₂