Question

The following is a chemical reaction: w Al   +  x MnO2   ---heat----> y Al2O3     +  z Mn w, x, y and z are the coefficients obtained on balancing the above equations. Find the values of w, x, y & z​

Answer 1

The unbalanced chemical reaction is Al(s)+O

2

(g)→Al

2

O

3

(s)

Balance Al atoms by adding 2 to Al on LHS

2Al(s)+O

2

(g)→Al

2

O

3

(s)

Balance O atoms by adding

2

3

to O

2

on LHS

2Al(s)+

2

3

O

2

(g)→Al

2

O

3

(s)

Multiply the whole equation with 2.

4Al(s)+3O

2

(g)→2Al

2

O

3

(s)

This is the balanced chemical equation. The coefficient of O

2

is 3.

Answer 2

w,x,y,z are 4,3,2,3.

• Al is a metal of group IV of modern periodic table.
• Aluminium reacts with $MnO_2$ to give aluminium oxide along with Mn.
• The reaction is-

$4Al+3MnO_2\rightarrow 2Al_2O_3+3Mn$

• In this reaction four moles of Aluminium reacts with three moles of $MnO_2$ to give two moles of aluminium oxide along with three moles of Mn.
• So, w,x,y,z are 4,3,2,3.