Science, Maths CBSE / ICSE Worksheets , Mcq's : chemistry cbse class 10

(Q.11) Metals react with dilute sulphuric acid to form:

(a) Metal hydroxide and sulphur trioxide
(b) Metal sulphite and water
(c) Metal sulphide and sulphur dioxide gas
(d) Metal sulphate and hydrogen gas

(Q.14) The metal extracted from calamine ore is-

(a) Calcium
(b) Zinc
(c) Copper
(d) Iron

(Q.15) Which of the following is true for ionic compounds?

(a) These compounds have low melting points and boiling points.
(b) These are soluble in organic solvents.
(c) These are good conductors of electricity.
(d) These do not conduct electricity.

(Q.16) Metals react with nonmetals to form ionic compounds by-

(a) Sharing of electrons
(b) Transfer of electrons
(c) Forming polar bonds
(d) Forming dative bonds

(Q.17) Which of the following compound is soluble in ether?

(a) Sodium chloride
(b) Magnesium chloride
(c) Methyl chloride
(d) Aluminium chloride

(Q.18) Galvanization is a method of protecting steel and iron

(a) By coating them with a thin layer of zinc
(b) By greasing the layer
(c) By anodizing
(d) By making alloys

(Q.19) A homogeneous mixture of two or more metals, or a metal and a non-metal is termed as

(a) Alloy
(b) Slag
(c) Charge
(d) Gangue

(Q.20) Corrosion of iron takes place in the presence of-

(a) Oxygen only
(b) Water only
(c) Oxygenand water bothin air
(d) Sulphur

(Q.21) Reaction of metal oxides with Aluminium is-

(a) Highly exothermic
(b) Highly endothermic
(c) Neither exothermic nor endothermic
(d) Not possible

(Q.22) In electrolytic method of refining of metals

(a) Anode is made of pure metal
(b) Cathode is made of pure metal
(c) Cathode is made of impure metal
(d) Anode is always made of graphite.

(Q.23) Sulphide ores are converted into oxides by

(a) Calcination
(b) Roasting
(c) Reaction with acids
(d) Reactionwith bases

(Q.24) Carbonate ores are converted into oxides by

(a) Calcination
(b) Roasting
(c) Reaction with acids
(d) Reaction with bases

(Q.25) Which type of bond is present in CCl₄?

(a) Ionic bond
(b) Covalent bond
(c) Electrovalent bond
(d) Dative bond

(Q.26) A non-metal used to preserve food material is-

(a) Carbon
(b) Sulphur
(c) Phosphorus
(d) Nitrogen

(Q.27) A substance from which a metal can be profitably extracted is called:-

(a) Mineral.
(b) Ore.
(c) Gangue.
(d) Crust.

(Q.28) A metal used for galvanizing iron is-

(a) Copper
(b) Zinc
(c) Potassium
(d) Sodium

(Q.29) Which of the following can conduct electricity?

(a) Sulphur
(b) Phosphorus
(c) Graphite
(d) Nitrogen

(Q.30) Metals does not liberate hydrogen gas on reaction with

(a) Hydrochloric acid
(b) Acetic acid
(c) Nitric acid
(d) Sulphuric acid

(Q.31) Na₂O and K₂O are

(a) Acidic oxides
(b) Basic oxides
(c) Neutral oxides
(d) Amphoteric oxides

(Q.32) The coreect decreasing order of reactivity of Al, Mg,Zn and Fe is

(a) Al>Fe>Zn>Mg
(b) Zn> Al> Fe >Mg
(c) Fe>Zn>Al>Mg
(d) Mg>Al>Zn>Fe

(Q.33) Best conductor of electricity is

(a) Silver
(b) Copper
(c) Aluminum
(d) Diamond

(Q.34) Metals conduct heat because:-

(a) Its atoms gain energy on heating, vibrate more vigorously and transfer the energy to the adjacentelectrons.
(b) Heating causes expansion that in turn conducts the heat.
(c) Heating is done all over the metal.
(d) Heating causes contraction that in turn conducts the heat.

(Q.35) Define ores.

(Q.36) What are alloys?

(Q.37) What chemical process is used for obtaining a metal from its oxides?

(Q.38) Define a chemical bond.

(Q.39) Which metal foil is used in packing of some medicine tablets?

(Q.40) Define corrosion.

(Q.41) What is flux?

(Q.42) What are the metals?

(Q.43) What happens when metals react with acids?

(Q.44) What are amphoteric oxides?

(Q.45) Which out of the following is not found in a free state?

(a) Gold
(b) Magnesium
(c) Silver
(d) Platinum

(Q.46) Aqua regia consists of HCl and HNO₃ in the ratio:

(a) 3 : 1
(b) 1 : 3
(c) 2 : 1
(d) 1 : 2

(Q.47) Themetal which burns in air with a dazzling white flame is

(a) Sodium
(b) Iron
(c) Copper
(d) Magnesium

(Q.48) Name two metals which are found in the nature in free state.

(Q.49) What do you understand by activity or reactivity series of metals?

(Q.50) Name two metals which are found in nature in the free state.

(Q.51) ____ is the most ductile metal.

(a) Silver
(b) Gold
(c) Aluminium
(d) Copper

(Q.52) Name the non-metal which conducts electricity.

(a) Diamond
(b) Graphite
(c) Silver
(d) Chlorine

(Q.53) What do you understand by activity or reactivity series of metals?

(Q.54) The arrangement of phosphorous, silicon, oxygen and sulphur in the order of their abundance in earth’s crust is

(a) phosphorous>silicon>oxygen>sulphur.
(b) oxygen>sulphur>phosphorous>silicon.
(c) oxygen>silicon>phosphorous>sulphur.
(d) sulphur>phosphorous>silicon>oxygen.

(Q.55) The non-metals can be solid, liquid and gaseous and are generally soft but hardest known natural substance diamond is also non-metal having melting point of about

(a) 2000⁰C.
(b) 2500⁰C.
(c) 3000⁰C.
(d) 3500⁰C.

(Q.56) Pair of metals that have very low melting points (less than 30⁰C) are

(a) sodium and gallium.
(b) potassium and cesium.
(c) gallium and cesium.
(d) sodium and potassium.

(Q.57) One of the following that is an amphoteric oxide is

(a) MgO.
(b) Al₂O₃.
(c) CaO.
(d) CuO.

(Q.58) The Al₂O₃ reacts with sodium hydroxide to form

(a) NaAlO.
(b) NaAlO₂.
(c) NaAlO₃.
(d) NaAlO₄.

(Q.59) Zinc oxide reacts with sodium hydroxide to form sodium zincate and water. The sodium zincate formed is

(a) Na₂ZnO₂.
(b) NaZnO₂.
(c) Na₂ZnO₃.
(d) NaZnO₃.

(Q.60) The iron metal in Fe₃O₄ is present as

(a) Fe(II) ions.
(b) Fe(III) ions.
(c) Simple iron atoms with no charge.
(d) Combination of Fe(II) and Fe(III) ions.

(Q.61) Arrangement of sodium, magnesium, calcium and potassium in the order of increasing abundance in earth’s crust is

(a) Sodium>magnesium>calcium>potassium.
(b) Magnesium>calcium>potassium>sodium.
(c) Calcium>potassium>sodium>magnesium.
(d) Calcium>sodium>potassium>magnesium.

(Q.62) The metals lose their shine or brightness on keeping in air for a long time and acquire a dull appearance due to

(a) the disintegration of their molecules into smaller components.
(b) formation of ions in their reactions with moisture.
(c) formation of free radicals on intermolecular interactions.
(d) the formation of oxides, carbonates and sulphides on their surfaces due to slow reactions with air.

(Q.63) The metal that forms oxidesinstead ofhydroxides, on reaction with water in any form (liquid or steam) is

(a) aluminium.
(b) magnesium.
(c) calcium.
(d) potassium.

(Q.64) The component of atmospheric air whose presence reduces the rate of combustion and makes it safer for living beings is

(a) oxygen.
(b) hydrogen.
(c) nitrogen.
(d) carbon dioxide.

(Q.65) On the basis of the vigour of their reaction with steam, the zinc, magnesium, iron and aluminium can be arranged as

(a) Mg>Al>Zn>Fe.
(b) Al>Zn>Fe>Mg.
(c) Zn>Fe>Mg>Al.
(d) Fe>Mg>Al>Zn.

(Q.66) All the mineral acids except one evolve hydrogen gas on reaction with reactive metals. This exceptional acid is

(a) Hydrochloric acid.
(b) Nitric acid.
(c) Sulphuric acid.
(d) Phosphoric acid.

(Q.67) Aquq-regia is a freshly prepared mixture of concentrated nitric acid and concentrated hydrochloric acid in the ratio

(a) 1:3 respectively.
(b) 2:3 respectively.
(c) 3:1 respectively.
(d) 3:2 respectively.

(Q.68) The commonly occurring metal iron is a heavy substance having high density. Its exact density is

(a) 6.8 gcm^-3.
(b) 7.8 gcm^-3.
(c) 8.8 gcm^-3.
(d) 9.8 gcm^-3.

(Q.69) The highly unreactive metal gold can be dissolved in

(a) Conc. H₂SO₄.
(b) Conc. HNO₃.
(c) Conc. HCl.
(d) aqua-regia.

(Q.45) Colour of the fumes of nitrogen dioxide (NO₂) is:

(a) Yellow
(b) Red
(c) Brown
(d) Blue

(Q.46) Chemical used in the photography is:

(a) Silver bromide
(b) Silver nitrate
(c) Sodium chloride
(d) Potassium chloride

(Q.47) The rusting of iron is

(a) an oxidation reaction.
(b) a reduction reaction.
(c) a redox reaction.
(d) a double decomposition reaction.

(Q.48) When a piece of magnesium metal is placed in blue coloured copper sulphate solution, the colour of solution fades due to the formation of

(a) magnesium oxide.
(b) copper oxide.
(c) magnesium sulphate.
(d) copper sulphite.

(Q.49) The chemical reaction between sulphur dioxide gas and acidified potassium dichromate is characterized by a change in colour from

(a) purple to green.
(b) orange to green.
(c) purple to orange.
(d) green to purple.

(Q.50) The chemical reaction between quicklime and water to form slaked lime is characterized by rise in temperature. Such reactions are called

(a) endothermic reactions.
(b) exothermic reactions.
(c) isothermal reactions.
(d) adiabatic reactions.

(Q.51) In the following oxidation-reduction reaction
, the reducing agent is

(a) chlorine.
(b) manganese dioxide.
(c) hydrochloric acid.
(d) hydrogen.

(Q.52) The reactions that take place with the fall in temperature are called endothermic reactions. One example of endothermic reactions is

(a) reaction between barium hydroxide and ammonium chloride.
(b) reaction between zinc granules and dilute sulphuric acid.
(c) reaction between quicklime and water.
(d) respiration by human beings.

(Q.53) The reaction amongst the following in which a black substance changes to reddish brown substance is

(a)

(b)

(c)

(d)

(Q.54) When an iron object is left in damp air for a considerable time, it gets covered with a red-brown flaky substance called “rust”. The rust is chemically

(a) hydrated iron oxide.
(b) hydrated iron carbonate.
(c) hydrated iron sulphate.
(d) hydrated iron oxalate.

(Q.55) The sign for heating in a balanced chemical equation is

(a)

.
(b)

(c)

.
(d)

(Q.56) Methyl alcohol is manufactured from carbon monoxide and hydrogen at 300 atmosphere pressure and 300⁰C temperature. The catalyst for this reaction is a mixture of

(a) ZnO and CrO₃.
(b) MoO and ZnO.
(c) MoO and CrO₃.
(d) VO₃ and CrO₃.

(Q.57) During photosynthesis, plants manufacture their food in green leaves by using chlorophyll and sunlight to form glucose and oxygen. The reactants required forthis vital processare

(a) water and carbon monoxide.
(b) carbon dioxide and carbon monoxide.
(c) water and carbon dioxide.
(d) water and air.

(Q.58) Lime that is used in large scale manufacture of cement is

(a) CuO.
(b) CaO.
(c) CuCO₃.
(d) CaCO₃.

(Q.59) When lead nitrate is heated strongly, it breaks down to form simpler substances. The brown fumes in the products of this reaction are due to the formation of

(a) NO.
(b) N₂O.
(c) NO₂.
(d) N₂O₃.

(Q.60) Green coloured crystals are formed by

(a) ZnSO₄.7H₂O.
(b) FeSO₄.7H₂O.
(c) MgSO₄.7H₂O.
(d) CuSO₄.5H₂O.

(Q.61) Any reaction in which an insoluble solid is formed that separates out from the solution as solid is precipitation reaction. One example of precipitation reaction is

(a)