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Question
When a black metal compound XO is heated with a colourless gas Y2, then metal X and another compound Y2O are formed. Metal X is red-brown in colour which does not react with dilute acids at all. Gas Y2 can be prepared by the action of a dilute acid on any active metal. The compound Y2O is a liquid at room temperature which can turn anhydrous copper sulphate blue.
- What do you think is metal X?
- What could be gas Y2?
- What is compound XO?
- What is compound Y2O?
- Write the chemical equation of the reaction which takes place on heating XO with Y2.
- What type of chemical reaction is illustrated in the above equation?
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Solution
- Metal X is copper. It is a red-brown metal that is less reactive than hydrogen and does not react with dilute acids.
- Gas Y2 is hydrogen (H2). It is a colourless gas produced by reacting active metals (such as zinc) with dilute acids.
- The compound XO is copper(II) oxide (CuO). It is a black copper compound.
- The compound Y2O is water (H2O). Water is a liquid at room temperature that turns white anhydrous copper sulphate blue (due to hydration).
- \[\ce{CuO + H2 -> Cu + H2O}\]
- This is a redox reaction or a displacement reaction. Hydrogen reduces copper(II) oxide to copper while itself getting oxidised to water.
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