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NEET levelSingle correct optionDifficulty 1 of 3rx011

The oxidation number of phosphorus in phosphorous acid, $H X_{3} PO X_{3}$ , is

A $+ 1$
B $+ 5$
C $+ 3$
D $+ 4$

Answer: C

3 (+ 1) + x + 3 (- 2) = 0

gives

x = + 3

. Taking the formula of phosphoric acid (

+ 5

) is a common slip.

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