Chemistry
Copper shows variable valency and forms two different compounds with oxygen — Cu2O and CuO.
P — A is cuprous oxide, B is cupric oxide.
Q — A is cupric oxide, B is cuprous oxide.
R — A is copper (I) oxide, B is copper (II) oxide.
Only P
Only Q
Only R
Both P and R
Valency
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Answer
Both P and R
Reason — Certain elements exhibit more than one valency and they show variable valency.
For example, copper shows valency of 1 and 2 and forms compounds like, cuprous [copper(I)] oxide and cupric [copper(II)] oxide, respectively.
Hence, both P and R are true.
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