Science
Give reasons for the following :
(a) Certain metals are used for making cooking utensils.
(b) Hydrogen gas does not evolve when certain metals except Mg & Mn react with nitric acid.
Metals & Non-Metals
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Answer
(a) Certain metals such as copper and aluminium are used for making cooking utensils because they are good conductors of heat, allowing uniform heating of food. These metals also have high melting points, so they do not melt or deform while cooking.
(b) Hydrogen gas does not evolve when most metals react with nitric acid because nitric acid is a strong oxidizing agent. Instead of releasing hydrogen, it oxidizes hydrogen to water and gets reduced to nitrogen oxides such as NO, NO2, or N2O. However, magnesium (Mg) and manganese (Mn) are exceptions because they are highly reactive and can displace hydrogen from very dilute nitric acid before it gets oxidized. Therefore, hydrogen gas is evolved only in their reactions with nitric acid.
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