Question

(i) C + O2  CO2

(ii) H2 + O2  H2O

(iii) 2Pbo + C  Pb + CO2

(iv) Fe2O3 + 2Al  AL2CO3 + 2Fe Which one are balanced and unbalanced​

Answer 1

we have to check which ones are balanced and unbalanced ?

(i) C + O2 => CO2

(ii) H2 + O2 => H2O

(iii) 2PbO + C => Pb + CO2

(iv) Fe2O3 + 2Al => Al2CO3 + 2Fe

solution : An chemical equation is known as balance when mass of reactants = mass of products.

now option (i) C + O2 => CO2

mass of reactants = mass of (C + O2) = 12 + 32 = 44

mass of products = mass of CO2 = 44

here mass of reactants = mass of products

so it is balanced chemical equation.

option (ii) H2 + O2 => H2O

mass of reactants = mass of H2 and O2 = 2 + 32 = 34

mass of products = mass of H2O = 18

here mass of reactants ≠ mass of products

so it is unbalanced chemical equation.

(iii) 2PbO + C => Pb + CO2

mass of reactants = mass of 2PbO and C = 2 × 223 + 12 = 458

mass of products = mass of Pb and CO2 = 207 + 44 = 251

so it is unbalanced chemical equation

(iv) Fe2O3 + 2Al => Al2O3 + 2Fe

mass of reactants = mass of Fe2O3 and 2Al = 160 + 54 = 214

mass of products = mass of Al2O3 + 2Fe = 102 + 112 = 214

so it is balanced chemical equation