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Some Basic Concepts of Chemistry

Short Answer Type

231.

Calculate the mass of nitrogen supplied to the soil by 5Kg of urea [CO(NH₂)₂]?

Multiple Choice Questions

232.
20 mL solution of 0.1 M ferrous sulphate was completely oxidised using a suitable oxidising agent. What is the number of electrons exchanged?

1.204 x 10²²

193

1930

1.204 x 10²¹

1.204 x 10²¹

During oxidation of FeSO_4, Fe²⁺ ion is oxidises into Fe³⁺

Fe²⁺→ Fe³⁺+ e^-

i.e., 1e^- is transferred from FeSO₄ , i.e., from 1 molecule of Fe²⁺ ion.

$Now, molarity of {FeSO}_{4} solution = 0.1 M and volume of solution = 20 mL = \frac{20}{1000} L ∴ Number of moles = 0.1 \times \frac{20}{1000} = 0.002 ∵ In 1 mole {FeSO}_{4} number of molecules = 6.022 \times 10^{23} In 0.002 mol {FeSO}_{4}, number of molecules = 6.022 \times 10^{23} \times 0.002 = 1 \times 1.204 \times 10^{21} ∴ Number of electrons transferred = 1 \times 1.204 \times 10^{21}$