Metals and Nonmetals

The non-metal which is liquid at room temperature is

• Mercury

• Bromine

• Carbon

• Helium

Answer explanation

Bromine is the only non-metal which exists as a liquid at room temperature.

Bauxite is an ore of

• Iron

• Mercury

• Aluminum

• Copper

Answer explanation

Bauxite is a commercial ore of aluminum which consists largely of hydrated aluminum oxide, Al₂O₃.2H₂O.

The metal which is liquid at room temperature is

• Bromine

• Mercury

• Potassium

• Iodine

Answer explanation

Mercury is the only metal which exists as a liquid at room temperature.

The sulphide ores are converted into oxides by heating strongly in the presence of excess air. This process is known as

• Roasting

• Smelting

• Calcination

• Refining

Answer explanation

The process of heating the sulphide ore strongly in the presence of air to convert it into metal oxide, is known as roasting.

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In electrolytic refining, the cathode is made up of

• Pure metal

• Impure metal

• Alloy

• Metallic salt

Answer explanation

In electrolytic refining of a metal, the cathode is made up of pure metal whereas the anode is made up of impure metal.

Which of the following represent the correct order of decreasing reactivity?

• Mg > Al > Zn > Fe

• Mg > Zn > Al > Fe

• Al > Zn > Fe > Mg

• Mg > Fe > Zn > Al

Answer explanation

The decreasing order of the reactivity of the common metals is given below:

K, Na, Ca, Mg , Al, Zn, Fe, Pb, [H], Cu,Hg, Ag, Au

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An element reacts with oxygen to give a compound with a high melting point. This compound is also soluble in water. The element is likely to be

• Ca

• C

• Si

• Fe

Answer explanation

Calcium reacts with oxygen to give calcium oxide (CaO) which is having a high melting point and dissolves in water to form calcium hydroxide (Ca(OH)₂)along with the release of large amount of thermal energy.

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Which among the following is the most abundant metal found in the earth’s crust?

• Magnesium

• Aluminum

• Oxygen

• Iron

Answer explanation

Aluminum is the most abundant metal found in the earth’s crust.

Which of the following pairs of reactants will undergo a displacement reaction?

• CuSO₄ + Fe

• ZnSO₄ + Fe

• MgSO₄ + Fe

• Ca(SO₄)₂ + Fe

Answer explanation

As per the reactivity series of metals, iron is more reactive than copper metal so it can displace copper from copper sulphate solution and form iron (II) sulphate and copper:

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Galvanisation is a method of protecting steel and iron from rusting by coating them with a thin layer of

• Copper

• Aluminum

• Zinc

• Bauxite

Answer explanation

In this method a thin layer of zinc metal is deposited over the surface of steel or iron objects, which does not corrode on exposure to damp air and prevents the coated metals from rusting.