Materials: Metals & Non Metals- 2 - UPSC Sci Tech Free MCQ Test with solutions

Metal oxides are basic in nature. When metal oxides react with water, they form bases. Water soluble bases are called s alkalis.

Bases turns red litmus blue but acids turn blue litmus red. Litmus is extracted from lichens that give different colour with different pH.

Non-metals don't react with water but the non-metal oxides do react with water and they produce acids. One example is chlorine gas (chlorine oxide) reacts with clouds (water) to form acids which come down as acid rain.

Aluminium form a barrier layer of oxide on its surface which prevents the further corrosion of aluminium on heating in presence of water.

Most of the metals are hard but potassium is very soft metal which can be cut with knife. It is stored in kerosene oil to prevent accidental fire.

Oxides of non-metal are acidic in nature. Non-metal oxide like SO2 and NO2, when dissolve in water they form sulphuric acid and nitric acid respectively.

Metal oxides react with water to produce hydroxides of metal which are basic in nature.

Zn +CuSO₄→ZnSO₄ +Cu.Zn +CuSO₄→ZnSO₄ +Cu.If Zinc is added to copper sulphate solution, Copper is displaced by Zinc because zinc is more reactive than copper.

Copper is more reactive than Silver but less reactive than magnesium, zinc and iron. Reactivity depends upon ability to loose electrons more easily.

Metals reacts with oxygen to form metal oxide , which are basic in nature. Iron, copper and aluminium reacts with oxygen to form their respective oxides.

When calcium hydroxide (lime water) is passed through carbon dioxide gas water turns milky due to formation of calcium carbonate, which is soluble in water.

Metals that reacts with both acids and bases are called amphoteric. Amphoteric oxides are acidic as well as basic in nature.

Metals generally have 1, 2 or 3 electrons in their outermost orbit or valence shell. e.g.,

The number of valence electrons in sodium, magnesium and aluminium metals are 1, 2 and 3 respectively.

Homogenous mixture of two or more metal or non-metal is called alloy. Alloy of zinc and copper is called brass.

Zinc reacts with hydrochloric acid to form zinc chloride with evolution of hydrogen gas. Zn+2HCl→ZnCl₂+ H₂

When silver is added to copper nitrate solution, no reaction takes place because silver is less reactive than copper.

Formation of rust on metal surface like iron is also called as corrosion. Corrosion occurs in presence of water and oxygen.

The property of a metal by virtue of which metal can be drawn into thin wires is called ductility. Gold is the most ductile metal.

You can wear red gold jewellery with your pieces in white and yellow gold without worrying about the metals clashing. Pure gold is too soft for everyday wear, so it is alloyed with a mixture of metals like silver, copper, platinum, palladium, and zinc to give it strength and durability.

Solution : 

The correct option is Option C.

The calcium metal begins to bubble vigorously as it reacts with the water, producing hydrogen gas, and a cloudy white precipitate of calcium hydroxide.