8881 + Interview Questions in Chemistry in Class 10 Page 18 InterviewSolution

851.	Which of the following is an endothermic reaction ?
Answer» burning of coal decomposition of VEGETABLE matter process of RESPIRATION decomposition of CALCIUM carbonate into calcium oxide and carbondioxide ANSWER :D

Discussion

852.	What are weak acids ? Give two examples
Answer» SOLUTION :ACIDS which give a small concentration of `H^+` IONS in water are WEAK acids. Examples : ACETIC acid and tartaric acid.

Discussion

853.	What happens when water is added to quick lime ? Write chemical equation.
Answer» Solution :A hissing sound is heard. A BRISK REACTION takes place and calcium hydroxide is formed. A lot of HEAT is also PRODUCED `CaO+H_(2)OtoCa(OH)_(2)`

Discussion

854.	What is meant by reactivity series of metals ? What is the reason for different reactivities of metals ?
Answer» Solution :`{:("Electrolysis","Reduction using carbon","FOUND in NATIVE place"),("K","Zn","Ag"),("Na","Fe","Au"),("Ca","Pb",),("MG","Cu",),("Al",,):}` On the basis of reactivity of different metals with oxygen, water and acids as well as displacement reactions, the metals have been arranged in the decreasing order of their REACTIVITIES. The arrangement of metals in order of decreasing reactivities is called reactivity series or activity series of metals. Reasons for different reactivities. In the activity series of metals, the basis of reactivity is the tendency of metal to lose electrons. If a metal can lose electrons easily to form positive ions, it will react readily with other substances. Therefore, it will be reactive metal. On the other hand, if a metal LOSES electrons less rapidly to form a positive ion, it will react slowly with the other substances.

Discussion

855.	What are alloys ?How are they prepared ?
Answer» Solution : An Alloy is a homogeneous mixture of a METAL with other metals or with NON - metals that are fused together . * e.g Brass is an alloy of zinc (solute ) in COPPER (solvent) * ALLOYS are prepared by fusingthe metals together . * Alloys are prepared by compressingfinely divided metals ONE over the other .

Discussion

856.	What will happen to blue litmus when it is added to soda water ?
Answer» SOLUTION :The COLOUR of LITMUS will TURN RED

Discussion

857.	Vinegar is :
Answer» 25% ACETIC ACID 6-8% acetic acid Pure acetic acid 50% acetic acid ANSWER :B

Discussion

858.	What is meant by oxidation and reduction reactions ? Explain it by giving examples
Answer» Solution :Chemical REACTION in which a substance (atom or MOLECULE) gains oxygen or loses hydrogen is called an OXIDATION reaction. For example `C+O_(2) to CO_(2)` `2Mg+O_(2) to 2MgO` `2Cu+O_(2) to 2CuO` In above reactions, C, Mg and Cu gain oxygen, and undergo oxidation reactions. Chemical reaction in which a substance (atom or molecule) loses oxygen or gains hydrogen is called reduction reaction. For example, `CuO + H_(2) toCu + H_(2)O` ` CO_(2) + H_(2) toCO + H_(2)O` `MGO + H_(2) to Mg + H_(2)O` In above reactions, `CuO, CO_(2)` and MgO lose oxygen. Hence, these are reduction reactions.

Discussion

859.	What type of oxide would eka-aluminium form?
Answer» `EO_3` `E_3O_2` `E_2O_3` `EO` ANSWER :C

Discussion

860.	What happens when dilute hydrochloric acid is added to iron filling ? Tick the correct answer.
Answer» HYDROGEN gas and iron chloride are PRODUCED. Chlorine gas and iron hydroxide are produced. No reaction TAKES place. Iron salt and watr are produced. SOLUTION :`Fe+2HCl to underset("chloride")underset("Iron")(FeCl_(2))+H_(2)` Thus, answer (a) is orrect.

Discussion

861.	Which of the following reaction will not take place ?
Answer» `Zn+FeSO_(4) to ZnSO_(4)+Fe` `2KI+Cl_(2) to +2KCl+I_(2)` `Zn+MgSO_(4) to ZnSO_(4)+Mg` `Mg+CuSO_(4) to MgSO_(4)+Cu` Answer :C

Discussion

862.	Write one difference between a mineral and an ore.
Answer» Solution :Naturally occurring COMPOUNDS of metals are CALLED MINERALS, whereas ore is a MINERAL from which the metal is EXTRACTED.

Discussion

863.	Which water is considered to be suitable for wishing purposes ?
Answer» SOLUTION :SOFT WATER .

Discussion

864.	Which of the following isa hydrate salt ?
Answer» `CU(OH)_2` `MgCO_3` `MgSO_4 . 7H_2 O ` `BaSO_4` ANSWER :C

Discussion

865.	Which of the following acts as both Bronsted acid and Lewis acid ?
Answer» `Cu^(+2)` `SO_(2)` `FE^(+3)` `NH_(4)^(+)` Answer :D

Discussion

866.	Vitamin C is essential for the prevention of scurvy. Combustion of 0.2000g of vitamin C gives 0.2998g of CO_(2) and 0.819g of H_(2)O. What is the empirical formula of vitamin C ?
Answer» ANSWER :`C_(3)H_(4)O_(3)`

Discussion

867.	Which of the following is a renewable natural resource ?
Answer» COAL PETROLEUM Air NATURAL gas Answer :C

Discussion

868.	Which of the following pair is in example of isotopes?
Answer» `""_(21)Sc^(45) and ""_(23)V^(50)` `""_(22)Ti^(48) and ""_(22)Ti^(50)` `""_(22)Ti^(50) and ""_(23)V^(50)` `""_(21)Sc^(45) and ""_(22)Ti^(50)` SOLUTION :`""_(22)Ti^(48) and ""_(22)Ti^(50)`

Discussion

869.	Which of the following reaction is feasible ?
Answer» `3Cu + Al_(2)(SO_(2))_(3) to 3CuSO_(4) +2AL` `Fe + ZnSO_(4) to FeSO_(4) +Cu` `CUSO_(4)+ Fe to FeSO_(4) + Cu` `Cu + ZnSO_(4) to CuSO_(4) + Zn` Answer :C

Discussion

870.	What type of oxides are formed when non-metals combine with oxygen ?
Answer» SOLUTION :NEUTRAL or ACIDIC OXIDES.

Discussion

871.	Write the molecular formula of the acid from which the ester (whose formula is given below) has been derived : H-underset(H)underset(\|)overset(H)overset(\|)( C)-overset(O)overset(\|\|)(C)-O-underset(H)underset(\|)overset(H)overset(\|)( C)-underset(H)underset(\|)overset(H)overset(\|)( C)-underset(H)underset(\|)overset(H)overset(\|)( C)-H
Answer» SOLUTION :`H-UNDERSET(H)underset(\|)OVERSET(H)overset(\|)(C )-overset(O)overset(\|\|)(C )-O-H` Ethanoic ACID.

Discussion

872.	What happens when nitric acid is added to egg shell ?
Answer» Solution :Egg shells contain calcium CARBONATE. When nitric acid is added to it, carbon dioxide GAS is evolved. The reaction can be GIVEN as `CaCO_(3) + 2HNO_(3) rarr CA(NO_(3))_(2) + H_(2)O + CO_(2)`

Discussion

873.	The steady decrease in size of lanthanide elements and their ions is called lanthanide contraction. In lanthanide elements, the differentiating electron enters into antepenultimate 'f-' subshell. (a) How does the entry of differentiating electron into antepenultimate shell affect the atomic and ionic sizes? Densities of 6th period elements are double to those of 5th period elements. Why?
Answer» Solution :(a) In lanthanide elements, the NEWLY added electron enters into anti-PENULTIMATE shell keeping the configurationn of penultimate and valence shells same. The ADDITION of electrons to inner shell should result in increased screening effect. But the 'f-' subshell has a very POOR screening effect. So the addition of electrons to the innerr 'f-" subshell does not result in corresponding increase in atomic size Therefore, the increasing nuclear charge fron cerium to lutetium (71) results in drastic decrease in atomi and ionic size. (b)Between the 5th and 6th periods, the intervening lanthanides increase the nuclear charge and lanthanide contraction results in decrease of atomic size. as a reuslt of this, MASS of atom increases and atomic size deceases. This results in drastic increase in density of elements from the 5th to 6th periods.

Discussion

874.	Write the name and formula of the 2^("nd") member of homologous series having general formula C_(2)H_(2).
Answer» Answer :PROPYNE, `C_(3)H_(4)`.

Discussion

875.	White phosphorus is stored in
Answer» ether water alcohol KEROSENE OIL ANSWER :B

Discussion

876.	We use colours dissolved in water during Holi and clothes gets spoiled. Many colours used to celebrate Holi are oxidized metals or industrial dyes mixed with engine oil. Doctors say these are harmful colours which should be banned for usage. Manufactures mix dyes with colours, and sell them for their profits. Holi lovers can make their Holi colourful by using natural colours available in the market.Natural colours start fading when they come in contact with sun rays. (i) Why doctors say that synthetic colours are harmful? (ii) What are natural colours? (iii) As a student what initiative you will take to motivate your classmates to use natural colours in Holi? Give any suggestions.
Answer» Solution :(i) Doctors SAY these colours are TOXIC and can cause skin allergies, eye irritation and BLINDNESS. (ii) The colours derived from vegetables and other organic sources are KNOWN as NATURAL colours. Suggestions: (a) Doctors consultancy in the class to satisfy the classmates. (b) Application of natural colours in class.

Discussion

877.	What is colloid ?
Answer» SOLUTION :A colloid is a hetergeneous solution of two or more SUBSTANCES in which the sizes of the PARTICLES lie between ` 10^(-7) cm and 10(-5)`cm. A colloid is stable.

Discussion

878.	When ethanol reacts with ethanoic acid in the presence of conc. H_(2)SO_(4), a substance with fruity smell is produced. Answer the following: (i) State the class of compounds to which the fruity smelling compounds belong. Write the chemical equaiton for the reaction and write the chemical name of the product formed. (ii) State the role of conc. H_(2)SO_(4) in this reaction.
Answer» SOLUTION :(i) The fruity smell compounds are: esters. Chemical EQUATION: `CH_(3)-overset(O)overset(\|\|)C-OH+CH_(3)CH_(2)OH overset("CONC. "H_(2)SO_(4))to CH_(3)-overset(O)overset(\|\|)C-O-CH_(2)-CH_(3)+H_(2)O` Product.s chemical name: Ethyl ethanoate. (ii) Conc. `H_(2)SO_(4)` acts as a dehydrating agent.

Discussion

879.	Which one of the following is not a straight chain hydrocarbon?
Answer» `CH_3 - CH_2 -CH_2 - CH_2 - CH_2 - CH_3` `undersetoverset(\|)(CH_3)(C)H_3 - CH_2 -CH_2 - CH_2 - undersetoverset(\|)(CH_3)(C)H_2` `undersetoverset(\|)(CH_3)(C)H_2- CH_2 - CH_2 - CH_2 - CH_2` ANSWER :D

Discussion

880.	Which of the following sets of quantam numbers represent electron in hydrozen atom
Answer» 1,1,0 `+(1//2)` 1,0,0, `+(1//2)` 3,0,0 `-(1//2)` 4,2,1 `-(1//2)` ANSWER :B

Discussion

881.	Which of the following is dependent on temperature?
Answer» Molarity Molality Mole FRATION MASS PERCENTAGE ANSWER :A

Discussion

882.	Two unlabelled bottles contain ethane and ethene separately. Describe two chemical tests to identify the gases.
Answer» Solution :(i) An alkene decolourises BROMINE water, whereas ALKANE does not respond to THISTEST. (ii) An alkene decolourises alkaline solution of `KMnO_4`while alkane does not respond to this TEST.

Discussion

883.	What was the drawback of the Law of Octaves?
Answer» Solution :Law of Octaves FAILED to assign the position to the elements with large ATOMIC WEIGHTS.

Discussion

884.	What happens when (give only balanced equations and write the names of the reactants and products ) A mixture of sodium acetate and soda lime is heated.
Answer» SOLUTION : METHANE is FORMED

Discussion

885.	Which of the following pH values at 25^(@)C corresponds to the strongest acid ?
Answer» 2 4 6 8 Solution :The LOWER is the pH VALUES, the stronger is the ACID. Therefore pH VALUE of 2 corresponds to the strongest acid

Discussion

886.	What happens when metals are burnt in air ?
Answer» Solution :When METALS are burnt in air, we GET metal oxide. `Fe+underset("(From Air)")(O_(2))overset("Very high TEMP.")toFe_(2)O_(3)`

Discussion

887.	Zinc is a metal found in the middle of the activity series of metals. In nature, it is found as a carbonate ore, ZnCO_(3). Mention the steps carried out for its extraction from the ore. Support with equations.
Answer» Solution :Calcination : HEATING the ore STRONGLY in limited amount of oxygen. `ZnCO_(3) overset("Heat")rarr ZNO + CO_(2)` Reduction : Converting ZnO to ZN with the help of carbon. `ZnO + C rarr Zn + CO`

Discussion

888.	Which two of the following organic compounds belong to the same homologous series? C_(2)H_(6), C_(2)H_(6)O, C_(2)H_(6)O_(2), CH_(4)O
Answer» SOLUTION :`CH_(4)O and C_(2)H_(6)O` BELONG to the same homologous SERIES.

Discussion

889.	Which of the following is the largest in size?
Answer» `CL^(-)` `S^(2-)` `NA^(+)` `F^(-)` SOLUTION :`S^(2-)` is largest insize due to high ELECTRON to proton ratio.

Discussion

890.	Which element was not placed in Mendeleev's periodic table properly?
Answer» SOLUTION :HYDROGEN

Discussion

891.	When a magnesium ribbon burns in air with a dazzling white flame and forms a white ash, is magnesium oxidzed or reduced ? Justify your answer with the help of a chemical equation.
Answer» SOLUTION :MAGNESIUM is OXIDIZED. `2Mg+O_(2)to2MgO`.

Discussion

892.	What are Deliquescent substances?
Answer» SOLUTION :CERTAIN subsnceswhichare sohygroscopic, whenexposed to theatmosphericair atordinarytemperatures ,absorbenoughwaterand getcompletely. Suchsubstancesare calleddeliquescentsubstancesand thispropertyis calleddeliquesence ,

Discussion

893.	The red or Orange coating that forms on the surface of iron when exposed to air and moisture for some time is called
Answer» GALVANISATION ELECTROPLATING rust REDUCTION ANSWER :C

Discussion

894.	Which of the following is the most nonmetallic element ?
Answer» Br Cl P S Answer :A

Discussion

895.	What happens, when ammonium chloride is added to barium hydroxide ? What changes in temperature take place during the reaction ?
Answer» Solution :When ammonium chloride is added to barium HYDROXIDE, it forms barium chloride, ammonia and WATER. `underset("Barium hydroxide")(Ba(OH)_(2))+underset("Ammonium chloride")(2NH_(4)Cl) to underset("Barium chloride")(BaCl_(2))+underset("Ammonium")(2NH_(3))+underset("Water")(2H_(2)O)` During the reaction temperature is LOWERED SINCE the reaction is endothermic.

Discussion

896.	Which functional group is present in aldehyde ?
Answer» `{:("\"),("/"):}=O` `-COOH` `-CHO` `-OH` ANSWER :C

Discussion

897.	Unsaturated hydrocarbons add hydrogen in the presence of catalyst such as ......... to give saturated hydrocarbons.
Answer» SOLUTION :PALLADIUM, NICKEL (Pd/Ni)

Discussion

898.	Water taken from anywhere USA, France or India will have Hydrogen and Oxygen is same ration i.e 1:8 , This is as per law of
Answer» LAW of MULTIPLE Proportions Law of Definite Proportions Law of CONSERVATION of Mass None Answer :B

Discussion

899.	Which of the following solutions has the same concentration of H^(+) ions as 0.1 N HCl ?
Answer» 0.1 N `H_(2)SO_(4)` 0.3 N `H_(3)PO_(4)` 0.2 N `HNO_(3)` All of these Answer :A

Discussion

900.	The various conditions required for theliquefaction of gases A, B, C and D are given below:
Answer» Solution :Among A, B, C and D gases, D is themost easily liquefiable gas since THETEMPERATURE required is thehighest and PRESSURE required is thelowest. The easier liquefaction INDICATES greater intermolecularforces of attraction and hencelarger deviation from ideal behaviour. Theorder of ease of liquefaction is`D gt C gt B gt A`, thus the ASCENDING order ofextent of deviation fromideal behaviour could be `A lt B lt C lt D`.

Discussion

Explore topic-wise InterviewSolutions in .

Which of the following is an endothermic reaction ?

What are weak acids ? Give two examples

What happens when water is added to quick lime ? Write chemical equation.

What is meant by reactivity series of metals ? What is the reason for different reactivities of metals ?

What are alloys ?How are they prepared ?

What will happen to blue litmus when it is added to soda water ?

Vinegar is :

What is meant by oxidation and reduction reactions ? Explain it by giving examples

What type of oxide would eka-aluminium form?

What happens when dilute hydrochloric acid is added to iron filling ? Tick the correct answer.

Which of the following reaction will not take place ?

Write one difference between a mineral and an ore.

Which water is considered to be suitable for wishing purposes ?

Which of the following isa hydrate salt ?

Which of the following acts as both Bronsted acid and Lewis acid ?

Vitamin C is essential for the prevention of scurvy. Combustion of 0.2000g of vitamin C gives 0.2998g of CO_(2) and 0.819g of H_(2)O. What is the empirical formula of vitamin C ?

Which of the following is a renewable natural resource ?

Which of the following pair is in example of isotopes?

Which of the following reaction is feasible ?

What type of oxides are formed when non-metals combine with oxygen ?

What happens when nitric acid is added to egg shell ?

Write the name and formula of the 2^("nd") member of homologous series having general formula C_(2)H_(2).

White phosphorus is stored in

What is colloid ?

Which one of the following is not a straight chain hydrocarbon?

Which of the following sets of quantam numbers represent electron in hydrozen atom

Which of the following is dependent on temperature?

Two unlabelled bottles contain ethane and ethene separately. Describe two chemical tests to identify the gases.

What was the drawback of the Law of Octaves?

What happens when (give only balanced equations and write the names of the reactants and products ) A mixture of sodium acetate and soda lime is heated.

Which of the following pH values at 25^(@)C corresponds to the strongest acid ?

What happens when metals are burnt in air ?

Zinc is a metal found in the middle of the activity series of metals. In nature, it is found as a carbonate ore, ZnCO_(3). Mention the steps carried out for its extraction from the ore. Support with equations.

Which two of the following organic compounds belong to the same homologous series? C_(2)H_(6), C_(2)H_(6)O, C_(2)H_(6)O_(2), CH_(4)O

Which of the following is the largest in size?

Which element was not placed in Mendeleev's periodic table properly?

When a magnesium ribbon burns in air with a dazzling white flame and forms a white ash, is magnesium oxidzed or reduced ? Justify your answer with the help of a chemical equation.

What are Deliquescent substances?

The red or Orange coating that forms on the surface of iron when exposed to air and moisture for some time is called

Which of the following is the most nonmetallic element ?

What happens, when ammonium chloride is added to barium hydroxide ? What changes in temperature take place during the reaction ?

Which functional group is present in aldehyde ?

Unsaturated hydrocarbons add hydrogen in the presence of catalyst such as ......... to give saturated hydrocarbons.

Water taken from anywhere USA, France or India will have Hydrogen and Oxygen is same ration i.e 1:8 , This is as per law of

Which of the following solutions has the same concentration of H^(+) ions as 0.1 N HCl ?

The various conditions required for theliquefaction of gases A, B, C and D are given below: