Q2 of 28 Page 187

A reddish brown coloured element ‘X’ on heating in air, becomes a black coloured compound ‘Y’. X and Y are______ and ________(Cu, CuO / Pb, PbO).

Cu,CuO

Copper (element ‘X’) is reddish brown in colour which upon heating in air reacts with the oxygen present in it or gets oxidised to form Copper(II) oxide(compound ‘Y’) which is black in colour.




More from this chapter

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1

Zn + 2HCl → ZnCl2 + H2↑

The above reaction is an example of ______.

 3

A student tests the pH of pure water using a pH paper. It shows green colour. If a pH paper is used after adding lemon juice to water, what colour will he observe?

(Green / Red / Yellow)

 4

Chemical volcano is an example of _________.

(combination reaction / decomposition reaction)

 5

When crystals of lead nitrate on heating strongly produces _________ gas and the colour of the gas is _________.