Same quantity of electricity was passed through solutions of sales of elements $X, Y$ and $Z$ with atomic…

Same quantity of electricity was passed through solutions of sales of elements $X, Y$ and $Z$ with atomic masses 7,27 and 48 respectively. The mass of $X, Y$ and $Z$ deposited were $2.1 \mathrm{~g}, 2.7 \mathrm{~g}$ and $7.2 \mathrm{~g}$ respectively. The valence's of $X, Y$ and $Z$ respectively are
  1. 3,2 and 1
  2. 1,2 and 3
  3. 1,3 and 2
  4. 2,3 and 1

Solution

According to Faraday's law $ \begin{array}{rlr} W & =Z Q & {[W=\text { weight of substance }]} \\ & =\frac{E Q}{96500} \quad[E=\text { Equivalent weight }] \end{array} $ For $X$ $ 2.1=\frac{(7 / x) Q}{96500} $ For $Y$ $ 2.7=\frac{(27 / y) Q}{96500} $ For $Z$ $ \begin{aligned} 7.2 & =\frac{(48 / z) Q}{96500} \\ x: y: z & =\left(\frac{7}{2.1}\right):\left(\frac{27}{2.7}\right):\left(\frac{48}{7.2}\right) \\ & =3.33: 10: 6.66 \simeq 1: 3: 2 \end{aligned} $

Asked in: AP EAMCET 2021 (24 Aug Shift 1)

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