Question

Mention with reason the color changes observed when:
$A)$Silver chloride is exposed to sunlight
$B)$ Copper powder is strongly heated in the presence of oxygen
$C)$ A piece of zinc is dropped in copper sulphate solution.

Answer 1

Hint : Silver bromide and silver iodide are also significantly more photosensitive than is $AgCl$ . $AgCl$ quickly darkens on exposure to light by disintegrating into elemental chlorine and metallic silver. This reaction is used in photography and film.

Complete Step By Step Answer:
$A)$ Silver chloride is white in color and elemental silver is grey in color. Hence, the color change observed when white silver chloride is left exposed in sunlight is from white to grey.
The type of chemical reaction is photolytic decomposition reaction or photolysis. Photolytic decomposition reactions are those which require the presence of light.
When silver chloride is exposed to light, it decomposes to form silver metal and chlorine gas. $2AgCl \to 2Ag + C{l_2}$
$B)$ This is a combination reaction. Combination reaction is a reaction where two or more elements or compounds combine to form a single compound.
When copper metal is heated in presence of oxygen, it gets oxidized to form black color copper oxide
$Cu + {O_2} \to CuO$
$C)$ This is a displacement reaction. A displacement reaction is the one wherein the atom or a set of atoms is displaced by another atom in a molecule.
When a piece of zinc is dropped in $CuS{O_4}$ solution then zinc being more reactive displaces copper from copper sulphate and forms S zinc sulphate solution.
$CuS{O_4} + Zn \to ZnS{O_4} + Cu$ .

Note :
Copper sulfate is an aggravation. The typical courses by which people can get harmful openness to copper sulfate are through eye or skin contact, just as by breathing in powders and dusts. Skin contact may bring about tingling or eczema. Eye contact with copper sulfate can cause conjunctivitis, irritation of the eyelid covering, ulceration, and blurring of the cornea.