2599 + Interview Questions in Chemistry in Class 9 Page 18 InterviewSolution

851.	The isotopes of an element have mass numbers, A,A+1,A+2. The ratio of abundance of these isotopes is 3:2:4. Calcualte the average atomic mass of the element.
Answer» SOLUTION :Average atomic mass `=(Axx3+(A+1)2+(A+2)4)/(9)=(3A+2A+2+4A+8)/(9)=A+(10)/(9)`

Discussion

852.	The intermolecular forces in the liquid state of a substance are stronger than those in its solid state.
Answer» ANSWER :F

Discussion

853.	The intensity of scattered light depends on the type of collodial solution and the size of the colloidal particles.
Answer» ANSWER :1

Discussion

854.	The infraredradiations hit the earth with higher energy , and get reflected back with lower energy .
Answer» ANSWER :T

Discussion

855.	That the atom is indivisible was proposed by .
Answer» Rutherford DALTON BOHR Einstein ANSWER :B

Discussion

856.	The impurities that are associated with the are called_________
Answer» SOLUTION :N/A

Discussion

857.	The hydrocarbon used for welding purpose is
Answer» ethane ethyne ethene beczene Solution :he hydrocarbon USED for WELDING PURPOSES is ACET ylene (ethyne) since oxyacetylene flame produces a high temperature of `3800^@C`.

Discussion

858.	The hydrated salt of copper sulphate has colour (a) Red (b) White (c) Blue
Answer» ANSWER :C

Discussion

859.	The groups responsible for the colour of an organic compound is called ……………….
Answer» ISOTOPES AUXOCHROME chromogen CHROMOPHORE ANSWER :D

Discussion

860.	The group number of noble gases in the modern periodic table is ______
Answer» ANSWER :18

Discussion

861.	The government had a peoposal fo estabilshing a thermal power plant where coal would be the source of power .A panel has been sent to the site to examine the fersibility of the proposal .The farmers in thet area panicky that their soils may become less fertile and may even become unfit for cultivation. However, the panel members convinced them by giving an assurance that the best quality coal will be used in the plant to minizise the effect. Can you explain the reason why burning of coal makes the soil loses fertility and how quality of coal has a bearing on the above? What other effects does burning of coal have on the enviroment ?
Answer» Solution :Coal is formed from various ORGANIC compounds. In coal along with carbon, nitrogen and sulphur are also present in varying amounts. When the coal is burnt the N and S form corresponding oxides Which escape into the atmosphere. These oxides com bine with WATER forming their corresponding ACIDS namely `HNO_3` and `H_2SO_4`. These acids reach earth as acid rain. As a result, the acidity of soil increases. Anthracite coal is the BEST type of coal as it contains least percentage of'S'and'N'and minimises the effect of acidity of soil to the maximum extent

Discussion

862.	The given graph shows the heating curve for a pure substance. The temperature rises with time as the substance is heated : (a) What is the physical state of the substance at the points A, B, C and D ? What is the melting point of the substance ? (c ) What is its boiling point ? (d) What happens to the temperature while the substance is changing state ? (e ) The substance is not water. How can you judge from the graph ?
Answer» Solution :(a) At point A : The substance is in the solid state. At point B : The substance has started melting. It exists both in the solid and liquid states. At point C : The substance is in the liquid state. A point D : The substance has started boiling. It exists both in the liquid and gaseous states. (b) the melting point of the substance is `15^(@)C`. (c ) The boilingpoint of the substance is `110^(@)C`. (d) The TEMPERATURE REMAINS the same during the change of state. (e ) Had substance been water, its melting point should have been `0^(@)C` and boiling point `100^(@)C`. It is therefore, not water.

Discussion

863.	The give mixture contains three constituents A, B and C. The constituent A is a yellow coloured, solid element which dissolves in a liqued E. The constitudent C is a liquid which is used in cooking food and froms a solid fat on hydrogenation. (a) What do you thing could (i) constituent A, and (ii) liquid D be ? (b) What could (i) constituent B, and (ii) liquid E be (c) What could liquid C be ? (d) How will you secarate the mixture containing A, B and C ?
Answer» Answer :(a) (i) Sulphur (ii) Carbon disulphide (B) (i) Copper sulphate (ii) Water (c ) Vegatable oil (d) FILTER the mixture of A, B and C. C (oil) being liquid will be obtained as a filtrate. RESIDUE consists of A (aulphur) and B (copper sulphate). ADD water, shake and filter. A (sulphur) is obtained as residue. Evaporter filtrate to obtain B (copper sulphate).

Discussion

864.	The gaseous state of a substance has the maximum fluidity .
Answer» ANSWER :T

Discussion

865.	The gas produced when a piece of zinc is made to react with dilute sulphuric acid is
Answer» SULPHUR dioxide CARBON dioxide hydrogen hydrogen sulphide ANSWER :C

Discussion

866.	The formula of washing soda is .............. , whilethat of sodium sulphate is ............
Answer» SOLUTION :`Na_(2)CO_(3)*10H_(2)O, Na_(2)SO_(4)`

Discussion

867.	The formula of the oxide of an element M is M_(2)O_(3) The first four ionisation energies of the element M can be in the order
Answer» 120 KCAL ,2780 kcal,400 kcal and5098 k cal 210 kcal ,150 kcal ,370 kcal and 590 kcal 70 kcal ,100kcal ,105 kcal and 120 kcal 560 kcal , 410 kcal ,320 and 290 kcal ANSWER :A:C, B:d , C:b , D:Fe , Df:a

Discussion

868.	The formula of sodium carbonate is Na_(2)CO_(3) .
Answer» ANSWER :T

Discussion

869.	The decomposition of NO is studies by monitoring the concentration. Initially the concentration of NO is 2.33 moles/L and after 184 min it is reduced to 2.02 moles/L. The reaction takes place according to the equation 2NO to N_(2)+O_(2). Calculate the rate of production of N_(2).
Answer» Solution :`2NO implies N_(2)+O_(2)` Rate of DECOMPOSITION of NO `=(DELTA[NO])/(Delta t)=([2.33-2.02])/(184xx60)` `=2.8xx10^(-5) "mole"//L//s` Rate of PRODUCTION of `N_(2)=(1)/(2)xx ` rate of decomposition of NO `therefore` Rate of production of `N_(2)=(2.8xx10^(-5))/(2)=1.4xx10^(-5) " mole" //L//s`.

Discussion

870.	The critical temperatures of CO_2 gas and N_2 gas are 31^(@)C and -147^(@) C, respectively. Which gas is liquefied easily and why ?
Answer» Solution :Since the criticl temperature of `CO_2` is HIGH, the intermolecular forces of attraction among `CO_2`MOLECULES are more when COMPARED to `N_2`. Hence, `CO_2` will liquefy easily.

Discussion

871.	The critical temperature of gases A, B, C and D are -118^(@)C, -240^(@)C, 132^(@)C and 20^(@)C, respectively. Arrange them in the decreasing order of intermolecular force of attraction.
Answer» Solution :The higher the critical TEMPERATURE the more is the intermolecular force of ATTRACTION and they can be liquefied easily. Decreasing order of intermolecular force of attraction is `C GT D gt A gt B`.

Discussion

872.	The cream from the milk can be separated by ______ method.
Answer» ANSWER :CENTRIFUGATION

Discussion

873.	The correct formula of aluminium sulphate is AlSO_(4).
Answer» ANSWER :F

Discussion

874.	The correct electronic configuration of potassium is ………………. .
Answer» `2 , 8 , 9` `2 , 8 , 1` `2 , 8 , 8 , 1` `2 , 8 , 8 ,3` Answer :C

Discussion

875.	The conversion of liquid state into solid state is called………….(sublimation, fusion, condensation)
Answer» ANSWER :CONDENSATION

Discussion

876.	The change from solid sate to vapour state without passing through the liquid state is called………
Answer» VAPORISATION fusion sublimation freezing Answer :C

Discussion

877.	The conversion of a liquid into its vapour at its boiling point is called ........
Answer» SOLUTION :BOILING

Discussion

878.	The conversion of a gas directly into solid is called condensation.
Answer» ANSWER :F

Discussion

879.	The conversion of a gas into liquid is called
Answer» GASIFICATION SUBLIMATION CONDENSATION freezing Answer :C

Discussion

880.	The conversion of 300 K in the Celsius scale is
Answer» `120^(@)C` `100^(@)C` `27^(@)C` `30^(@)C` ANSWER :C

Discussion

881.	The constituents of a compoundcan be separated easily
Answer» ANSWER :F

Discussion

882.	The composition of a mixtureis always fixed
Answer» ANSWER :F

Discussion

883.	The components of water can be separated by
Answer» PHYSICAL METHOD CHEMICAL method Both They could not be SEPARATED ANSWER :B

Discussion

884.	The components of air can be separated by ______ process.
Answer» ANSWER :FRACTIONAL DISTILLATION

Discussion

885.	The components of a solution can be separted by filteration
Answer» ANSWER :F

Discussion

886.	The components of a colloidal can be separatedby .............
Answer» ANSWER :CENTRIFUGATION

Discussion

887.	The colouredcomponents present in a dye cfan be separted by a process knwn as chromatography
Answer» ANSWER :t

Discussion

888.	The colour of vapours formed on sublimation of iodine solid is
Answer» PURPLE COLOURLESS YELLOW ORANGE ANSWER :A

Discussion

889.	The colour of the precipitate obtained when an aqueous solution of sodium chlorideis treated with silvernitrate solution is
Answer» black YELLOWISH PINK CURDY white Answer :D

Discussion

890.	The colloid formed in liquid medium of the substance is called ______ .
Answer» ANSWER :EMULSION

Discussion

891.	The clothes dry faster on windy day.
Answer» ANSWER :1

Discussion

892.	The circulation of the essential nutrients between living and non-living components of the biosphere is termed as :
Answer» ANSWER :T

Discussion

893.	The chemistry of alkali metals is essentially the chemitry of unipositive ions becasuse
Answer» they have low IONISATION energy values they have STRONG tendency to LOSE single valenceelectron second ionidatin energy values are very high all the above ANSWER :d

Discussion

894.	The chemical symbol of iron is Ir.
Answer» ANSWER :F

Discussion

895.	The chemical symbol for helium is
Answer» `He_(2)` `He` `He^(+)` `He^(2+)` ANSWER :B

Discussion

896.	The chemical properties of isotopes are similar.
Answer» ANSWER :TRUE

Discussion

897.	The chemical equation BaCl_(2)+Na_(2)SO_(4)rarrBaSO_(4)+2NaCl represents following type of chemical reaction.
Answer» displacement Carbon is oxidized combination DECOMPOSITION ANSWER :A::B::C::D

Discussion

898.	The chemical equation BaCl_2+ Na_2SO_4to BaSO_4+2NaCl represents following type of chemical reaction.
Answer» displacement Carbon is oxidized combination DECOMPOSITION ANSWER :A::B::C::D

Discussion

899.	The charge/mass (e/m) ratio is maximum for
Answer» proton neutron electron positron Answer :C

Discussion

900.	The change of liquid into gas even without heating is called _____
Answer» ANSWER :EVAPORATION

Discussion

Explore topic-wise InterviewSolutions in .

The isotopes of an element have mass numbers, A,A+1,A+2. The ratio of abundance of these isotopes is 3:2:4. Calcualte the average atomic mass of the element.

The intermolecular forces in the liquid state of a substance are stronger than those in its solid state.

The intensity of scattered light depends on the type of collodial solution and the size of the colloidal particles.

The infraredradiations hit the earth with higher energy , and get reflected back with lower energy .

That the atom is indivisible was proposed by .

The impurities that are associated with the are called_________

The hydrocarbon used for welding purpose is

The hydrated salt of copper sulphate has colour (a) Red (b) White (c) Blue

The groups responsible for the colour of an organic compound is called ……………….

The group number of noble gases in the modern periodic table is ______

The gaseous state of a substance has the maximum fluidity .

The gas produced when a piece of zinc is made to react with dilute sulphuric acid is

The formula of washing soda is .............. , whilethat of sodium sulphate is ............

The formula of the oxide of an element M is M_(2)O_(3) The first four ionisation energies of the element M can be in the order

The formula of sodium carbonate is Na_(2)CO_(3) .

The decomposition of NO is studies by monitoring the concentration. Initially the concentration of NO is 2.33 moles/L and after 184 min it is reduced to 2.02 moles/L. The reaction takes place according to the equation 2NO to N_(2)+O_(2). Calculate the rate of production of N_(2).

The critical temperatures of CO_2 gas and N_2 gas are 31^(@)C and -147^(@) C, respectively. Which gas is liquefied easily and why ?

The critical temperature of gases A, B, C and D are -118^(@)C, -240^(@)C, 132^(@)C and 20^(@)C, respectively. Arrange them in the decreasing order of intermolecular force of attraction.

The cream from the milk can be separated by ______ method.

The correct formula of aluminium sulphate is AlSO_(4).

The correct electronic configuration of potassium is ………………. .

The conversion of liquid state into solid state is called………….(sublimation, fusion, condensation)

The change from solid sate to vapour state without passing through the liquid state is called………

The conversion of a liquid into its vapour at its boiling point is called ........

The conversion of a gas directly into solid is called condensation.

The conversion of a gas into liquid is called

The conversion of 300 K in the Celsius scale is

The constituents of a compoundcan be separated easily

The composition of a mixtureis always fixed

The components of water can be separated by

The components of air can be separated by ______ process.

The components of a solution can be separted by filteration

The components of a colloidal can be separatedby .............

The colouredcomponents present in a dye cfan be separted by a process knwn as chromatography

The colour of vapours formed on sublimation of iodine solid is

The colour of the precipitate obtained when an aqueous solution of sodium chlorideis treated with silvernitrate solution is

The colloid formed in liquid medium of the substance is called ______ .

The clothes dry faster on windy day.

The circulation of the essential nutrients between living and non-living components of the biosphere is termed as :

The chemistry of alkali metals is essentially the chemitry of unipositive ions becasuse

The chemical symbol of iron is Ir.

The chemical symbol for helium is

The chemical properties of isotopes are similar.

The chemical equation BaCl_(2)+Na_(2)SO_(4)rarrBaSO_(4)+2NaCl represents following type of chemical reaction.

The chemical equation BaCl_2+ Na_2SO_4to BaSO_4+2NaCl represents following type of chemical reaction.

The charge/mass (e/m) ratio is maximum for

The change of liquid into gas even without heating is called _____