JEE Main 2026 Jan 21 Shift 2, Chemistry Q5: Mole Concept And Equivalent Concept

JEE Main2026Jan 21, Shift 2Chemistry

By usual analysis, 1.00g of compound (X) gave 1.79g of magnesium pyrophosphate. The percentage of phosphorus in compound (X) is: (nearest integer)

(Given, molar mass in g mol $^{- 1}$ : O = 16, Mg = 24, P = 31)

Solution

$M g_{2} P_{2} O_{7}$ has molar mass $2 (24) + 2 (31) + 7 (16) = 48 + 62 + 112 = 222$ g/mol and contains 2 P atoms (mass $2 \times 31 = 62$ ).

Mass of P in 1.79 g of pyrophosphate: $\frac{1.79}{222} \times 62 \approx 0.4997$ g.

$%$ P in X: $\frac{0.4997}{1.00} \times 100 \approx 49.99% \approx 50%$ .

Concept behind this question

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