8881 + Interview Questions in Chemistry in Class 10 Page 9 InterviewSolution

401.	What is the colour of FeSO_4. 7H_2O crystals? How does this colour change upon heating? Give balanced chemical equation for the changes.
Answer» Solution :`FeSO_4. 7H_2O` is green in COLOUR and LOSES water of CRYSTALLISATION when it is heated. It is then dicomposed to `Fe_2O_3` (brown coloured), `SO_2 and SO_3` `FeSO_4. 7H_2O to^(Delta)FeSO_4+7H_2O` `2FeSO_4(s)to^(Delta)Fe_2O_3(s)+SO_2(G)+SO_3(g)`

Discussion

402.	Write the number of electrons in the outermost shell of Sodium
Answer» SOLUTION : NUMBER of ELECTRONS = 7

Discussion

403.	What is Combustion reaction?
Answer» SOLUTION :A combustion reaction is one in which the reactant rapidly combines with oxygen to FORM one or more oxides and energy(heat). e.g., `underset("Propane")(C_(3)H_(8(AQ)))+5O_(2(aq))to3CO_(2(g))+4H_(2)O_((g))4H_(2)O_(g)+Heat`

Discussion

404.	Which of the following is not a physical change ?
Answer» combustion of LPG melting of ICE dissolution of salt in water BOILING of water ANSWER :A

Discussion

405.	Why are aluminium and copper metals used for making cooking vessels ?
Answer» Solution :ALUMINIUM and copper metals are used for making cooking VESSELS because they are good CONDUCTORS of HEAT and they have high melting points.

Discussion

406.	Two samples of iron, A and B were given to two students, Rini and Riki, respectvely. One of the samples is wrought iron and the other is pig iron. They were asked to observe and study their properties. Rini found that the sample given to her broke easily, whereas Riki's sample was more malleable. Apart from this, it was observed that Rini's sample could be welded at a relatively lower temperaure than Riki's sample. Based on the above observations, identify A and B and justify your answer.
Answer» Solution :In wrought iron, CARBON CONTENT is much lesser than that in pig iron. Presence of carbon that is a non-metal reduces the malleability of a metal and the metal becomes HARD and brittle. Moreover presence of impurity reduces the meltin point of a solid. Hence pig iron, in which carbon content is more, can be welded at a which carbon content is more, can be welded at a lower temperature. From these two observations it can be concluded that RINI's sample is pig iron and RIKI's sample is wrought iron.

Discussion

407.	Two elements X and Y have atomic numbers 12 and 16 respectively. To which period of the modern periodic table do these two elements belong ? What type of bond will be formed between them and why?
Answer» Solution :Electronic configuration of element X, atomic number 12 = 2,8,2 Electronic configuration of element Y, atomic numbers 16 = 2,8,6 Both have three SHELLS, so they belong to period 3. They will FORM IONIC bond as X will form electropositive ion and Y will form electronegative ion.

Discussion

408.	Write two points difference between . Fused lead bromide and hot aqueous solution of lead bromide .
Answer» Solution :(i) In fused lead bromide , only `PB^(2+) and Br^(-)` ions namely , are present , whereasin a hot aqueous solution of lead bromide , four types of ionsnamely `Pb^(2+) , Br^(-) , H^(+) and OH^(-) ` ions are present . (ii) On electrolysis of fused lead bromide , lead is PRODUCED at cathode and bromine is produced at anode , However , in case of hot aqueous solution of lead bromide , HYDORGEN gas is producedat cathodeand bromine is produced at anode .

Discussion

409.	The value of e/m of an electron was measured by:
Answer» Millikan J. THOMSON Dalton utherford ANSWER :B

Discussion

410.	Use your brain power, What would be the expected trend in the variation of non-metallic character of elements down a group?
Answer» SOLUTION :Non-metallic CHARACTER DECREASES as we MOVE down a GROUP.

Discussion

411.	When Silica gel is kept open, it absorbs moisture from the air, because it is hygroscopic in nature.
Answer» ANSWER : TRUE

Discussion

412.	The structure of two organic compounds are given below: i) CH_3-CH_2-CH_2-CH_2-OH ii) CH_3-CH_2-O-CH_2-CH_3 Write the molecular formula of these com-pounds.
Answer» ANSWER :`C_4H_(10)O`

Discussion

413.	Which of the following is not a physical property?
Answer» SPECIFIC heat MELTING point REACTION with other elements or com pounds freezing point Solution : reaction with other elements or com pounds

Discussion

414.	Which one of the following is least dense?
Answer» MERCURY Gold SODIUM ALUMINIUM SOLUTION :Sodium

Discussion

415.	When 2.82 g of solid NH_(4)Cl is intoroduced into a 2 L flask at 30^(@)C. 40 per cent of the solid NH_(4)Cl decomposes into two gaseous products, that is NH_(3) and HCl. Calculate the Kc. What would happen if more amount of NH_(4)Cl is introduced into the flask ?
Answer» Solution :`NH_(4)Cl_((s)) HARR NH_(3(g))+ HCl_((g))` 2.82 g of `NH_(4)Cl` is subjectedto decomposition. Molecular weight of `NH_(4)Cl=14+4+35.5=53.5` `implies`No. of moles of `NH_(4)Cl=(2.82)/(53.5)=0.0527` Given that percent dissociation of`NH_(4)Cl` is 40 percent 0.0527 moles decomposition corresponds to 100 per cent? molesdecomposition corresponding to 40 per cent `=(40xx0.0527)/(100)=0.0210` `NH_(4)Cl hArr NH_(3) + HCl` `{:("Initial number of moles" ,0.0527,0,0),("Number of moles ",0.0527,,-0.0210),(,0.0210,,0.0210):}` at equilibrium =0.317 `therefore K_(c)=[NH_(3)][HCl]=(0.0210)/(2)xx(0.0210)/(2)` `=(0.0210xx0.0210)/(4)=1.1xx10^(-4) "mol"^(-4)//L^(2)` Addition of a solid or LIQUID REACTANT at equilibrium does not affect the equilibrium . So addition of solid `NH_(4)Cl` does not affect the equilibrium .

Discussion

416.	Translate the following statement into chemical equation and then balance it : ''A metal in the from of ribbon burns with a dazzling white flame and changes into a white powder'.
Answer» SOLUTION :Magnesium COMBINES with ATMOSPHERIC pxygen to from magnesium oxide. `2Mg+O_(2) rarr2MgO`

Discussion

417.	Write the balanced chemical equation for the following and identify the type of reaction in each case : Magnesium (s) + Hydrochloric acid (aq) to Magnesium chloride (aq) + Hydrogen (g)
Answer» Solution :Balanced EQUATION : `Mg(s)+2HCl(aq)toMgCl_(2)(aq)+H_(2)(g)` This is an EXAMPLE of DISPLACEMENT reaction because H in HCl has been DISPLACED by Mg.

Discussion

418.	When electricity is passed through a common salt solution, sodium hydroxude is produced along with the liberation of two gases X and Y. X burns with a pop sound whereas Y is used for disinfecting drinking water. (i) Identify X and Y (ii) Give tha chemical equation for the reaction stated above. (iii) State the reaction of Y with dry slaked lime.
Answer» Solution :(i) X - Hydrogen (ii) Y - Chlorine `2NaCl(AQ) + 2H_(2)O(l) rarr 2NaOH(aq) + Cl_(2)(g) + H_(2)(g)` (iii)Y + slaked lime `(Ca(OH)_(2))` (iv) `Ca(OH)_(2) + Cl_(2) rarr CaOCl_(2) + H_(2)O`

Discussion

419.	What is the name of the compound formed by the reaction between ethanol and ethanoic acid in the presence of concentrated sulphuric acid?
Answer» SOLUTION :ETHYL ethanoate

Discussion

420.	Write the balanced chemical equation for the following and identify the type of reaction in each case : Zinc carbonate (s) to Zinc oxide (s) + Carbon dioxide (g)
Answer» Solution :BALANCED EQUATION : `ZnCO_(3)(s)toZnO(s)+CO_(2)(G)` This is an example of DECOMPOSITION reaction.

Discussion

421.	Write the balanced chemical equation for the following and identify the type of reaction in each case : Potassium bromide (aq) + Barium iodide (a) to Potassium iodide (aq) + Barium bromide (s)
Answer» Solution :BALANCED equation : `2KBr(aq)+BaI_(2)(aq)to2KI(aq)+BaBr_(2)(s)` This is an EXAMPLE of double displacement reaction because the CATIONS `K^(+)` and `Ba^(2+)` have EXCHANGED their anions, `Br^(-)` and `SO_(4)^(2-)`.

Discussion

422.	Write the balanced chemical equation for the following and identify the type of reaction in each case : Hydrogen (g) + Chlorine (g) to Hydrogen chloride (g)
Answer» SOLUTION :Balanced equation : `H_(2)(G)+Cl_(2)(g)to2HCl(g)` This is an example of combination REACTION.

Discussion

423.	When concentrated solution of cupric chloride is taken, chlorine gets liberated at anode, in contrast to a dilute solution where oxygen is liberated. However, when aqueous solution of CuSO_(4) is taken, only oxygen is liberated at anode irrespective of concentration. How do yoy account for this ?
Answer» Solution :An AQUEOUS solution of cupric chloride contrains `Cl^(-)` ions, `OH^(-)` ions, `CU^(+2)` ions and `H^(+)` ions. Due to lower DISCHARGE POTENTIAL of `OH^(-) " than " Cl^(-)`, oxygen gas is liberated at anode in preference to chlorine. However, in the concetrated solution, as the concetration of `OH^(-)` ions is very low, only chlorine gets liberated at anode. This is possible because the difference between dischange potentials of `Cl^(-) and OH^(-)` is only marginal. An aqueous solution of `CuSO_(4)` contains `Cu^(+2), H^(+), OH^(-) and SO_(4)^(-2)` ions. Due to large difference in discharge potentials between `SO_(4)^(-2) and OH^(-), " only " OH^(-)` ions get discharged at anode irrespective of the concetration of the electrolyte

Discussion

424.	Which metal is isolated from cinnabar?
Answer» SOLUTION :MERCURY

Discussion

425.	which of thefollowingrepresentsaprecipitaion reaction ?
Answer» `A_((s)) +B_((s))to C_((s)) +D_((s))` `A_((s)) +B_((aq)) toC_((aq))+D_((l))` `A_((Aq))+B_((aq)) toC_((s))+D_((aq))` `A_((aq))+B_((s)) toC_((aq))+D_((l))` ANSWER :C

Discussion

426.	Which of the following is not a non-metal ?
Answer» COAL SULPHUR IODINE SODIUM Solution :Sodium is a METAL.

Discussion

427.	Which amongst the following statement is true?
Answer» all RAYS are cathode rays Electrons make up the cathode ray PROTONS make up the cathode rays configuration of Ca is 2,8,8 ANSWER :B

Discussion

428.	Which of the following correctly describes the magnetic field near a long straight wire?
Answer» The field CONSISTS of straight line PERPENDICULAR to the wire. The field consists of straight lines parallel to the wire. The field consists of radial lines originating from the wire. The field consists of concentric CIRCLES CENTRED on the wire. Solution : The field consists of concentric circles centred on the wire.

Discussion

429.	The spectator ions in the hydrolysis of (NH_(4))_(2) CO_(3) are
Answer» `NH_(4)^(+), H^(+), OH^(-)` `NH_(4)^(+), CO_(3)^(2-), H^(+), OOH^(-)` `CO_(3)^(2-), H^(+), OH^(-)` no SPECTATOR ions Answer :D

Discussion

430.	White chemical compound become hard on mixing proper quantity of water . It is also used in surgery to maintain joints in a fixed position . Name the chemical compound .
Answer» Solution :Plaster of PARIS (CALCIUM SULPHATE hemihydrate.)

Discussion

431.	Write word equations and then balanced equations for the reaction taking place when dilute sulphuric acid reacts with zinc granules
Answer» SOLUTION :Dilute SULPHURIC acid reacts with zinc granules forming zinc sulphate and EVOLVING hydrogen gas Zinc + Sulphuric acid `rarr` Zinc sulphate + Hydrogen `Zn(s)+H_(2)SO_(4)(aq) rarr ZnSO_(4)(aq) + H_(2)(G)`

Discussion

432.	Write word equations and then balanced equations for the reaction taking place when dilute sulphuric acid reacts with aluminium powder
Answer» Solution :Dilute sulphuric ACID reacts with aluminium powder to form aluminium sulphate with the evolution of hydrogen gas Aluminium + Sulphuric acid `RARR` Aluminium sulphate + Hydrogen `2Al(s) + 3H_(2)SO_(4)(aq) rarr Al_(2)(SO_4)_3(aq) + 3H_(2)(g)`

Discussion

433.	What is LPG ?
Answer» SOLUTION :LiquefiedpetroleumGasis amixtureofhydrocarbongaseslikepropane, butaneproptleneetc .

Discussion

434.	Which of the following molecules has (have) a triple bond
Answer» `CH_(4)` `C_(2)H_(4)` `C_(2)H_(2)` `NH_(3)` ANSWER :C

Discussion

435.	What happens when (give only balanced equations and write the names of the reactants and products ) Ethyl alcohol is heated with conc. H_2SO_4 at 170^@C
Answer» SOLUTION :ETHENE is FORMED

Discussion

436.	What happens when (give only balanced equations and write the names of the reactants and products )Ethene is allowed to combine with Cl_2 gas.
Answer» SOLUTION :DICHLOROMETHANE `(C_2H_4Cl_2)`is FORMED

Discussion

437.	What happens when (give only balanced equations and write the names of the reactants and products ) Ethene gas is burnt in oxygen.
Answer» SOLUTION :`2CO_2 , 2H_2O`and HEAT ENERGY are PRODUCED

Discussion

438.	What happens when (give only balanced equations and write the names of the reactants and products ) Ethyne reacts with chlorine.
Answer» Solution :EXPLOSIVE REACTION takes PLACE producing carbon and HCI

Discussion

439.	What happens when (give only balanced equations and write the names of the reactants and products ) Ethyne and hydrogen combine in the presence of a catalyst.
Answer» SOLUTION : FIRST ETHENE, then ETHANE is FORMED

Discussion

440.	What happens when (give only balanced equations and write the names of the reactants and products ) Ethyne reacts with excess of bromine.
Answer» SOLUTION :TETRABROMOETHANE `(CHBr_2 -CHBr_2)`is FORMED

Discussion

441.	Using the given part of the periodic table, answer the following questions with reason : (i) Name the element having smallest atomic size. (ii) Write electronic configuration of element E. (iii) Identify the elements which have similar physical and chemical properties as the element Y.
Answer» SOLUTION :(i) Element - E (ii) `{:("K","L","M"),("2","8","6"):}` (III) X and Z.

Discussion

442.	Which functional group is present in carboxylic acid ?
Answer» `{:("\"),("/"):}C=0` `-COOH` `-CHO` `-OH` ANSWER :B

Discussion

443.	What is covalent radius?
Answer» Solution : It is defined as HALF the DISTANCE between the NUCLEI of two covalently bonded atoms of the same ELEMENT in a MOLECULE.

Discussion

444.	What is the commercial name of calcium sulphate hemihydrate ?
Answer» SOLUTION :PLASTER of PARIS.

Discussion

445.	Which of the following d orbitals involved in Sp_(3)d hybridization?
Answer» `d_(XY)` `d_(xz)` `d_(x^(2)-y^(2))` `d_(Z^(2))` Answer :D

Discussion

446.	Which of the following metal oxide contains metal in two different valencies ?
Answer» `Al_(2)O_(3)` `Fe_(3)O_(4)` `MnO_(2)` `PbO_(2)` ANSWER :B

Discussion

447.	The scientist who heated tin in a retort to verify the law of convservation of mass in a chemical reaction
Answer» pristley LAVOISIER DALTON THOMSON ANSWER :B

Discussion

448.	Which among the following is a decomposition reaction ?
Answer» ELECTROLYSIS RUSTING PHOTOSYNTHESIS CORROSION ANSWER :A

Discussion

449.	Which of the statement about the following reactions is correct ? ZnO + CO to Zn + CO_(2)
Answer» ZNO is being oxidized. CO is being reduced `CO_(2)` is being oxidized ZnO is being reduced. Answer :D

Discussion

450.	Which of the pairs will give displacement reactions ?
Answer» NaCl solution and COPPER metal `MgCl_(2)` solution and aluminium metal `FeSO_(4)` solution and SILVER metal `AgNO_(3)` solution and copper metal Solution :`AgNO_(3)` solution and copper metal

Discussion

Explore topic-wise InterviewSolutions in .

What is the colour of FeSO_4. 7H_2O crystals? How does this colour change upon heating? Give balanced chemical equation for the changes.

Write the number of electrons in the outermost shell of Sodium

What is Combustion reaction?

Which of the following is not a physical change ?

Why are aluminium and copper metals used for making cooking vessels ?

Two elements X and Y have atomic numbers 12 and 16 respectively. To which period of the modern periodic table do these two elements belong ? What type of bond will be formed between them and why?

Write two points difference between . Fused lead bromide and hot aqueous solution of lead bromide .

The value of e/m of an electron was measured by:

Use your brain power, What would be the expected trend in the variation of non-metallic character of elements down a group?

When Silica gel is kept open, it absorbs moisture from the air, because it is hygroscopic in nature.

The structure of two organic compounds are given below: i) CH_3-CH_2-CH_2-CH_2-OH ii) CH_3-CH_2-O-CH_2-CH_3 Write the molecular formula of these com-pounds.

Which of the following is not a physical property?

Which one of the following is least dense?

When 2.82 g of solid NH_(4)Cl is intoroduced into a 2 L flask at 30^(@)C. 40 per cent of the solid NH_(4)Cl decomposes into two gaseous products, that is NH_(3) and HCl. Calculate the Kc. What would happen if more amount of NH_(4)Cl is introduced into the flask ?

Translate the following statement into chemical equation and then balance it : ''A metal in the from of ribbon burns with a dazzling white flame and changes into a white powder'.

Write the balanced chemical equation for the following and identify the type of reaction in each case : Magnesium (s) + Hydrochloric acid (aq) to Magnesium chloride (aq) + Hydrogen (g)

What is the name of the compound formed by the reaction between ethanol and ethanoic acid in the presence of concentrated sulphuric acid?

Write the balanced chemical equation for the following and identify the type of reaction in each case : Zinc carbonate (s) to Zinc oxide (s) + Carbon dioxide (g)

Write the balanced chemical equation for the following and identify the type of reaction in each case : Potassium bromide (aq) + Barium iodide (a) to Potassium iodide (aq) + Barium bromide (s)

Write the balanced chemical equation for the following and identify the type of reaction in each case : Hydrogen (g) + Chlorine (g) to Hydrogen chloride (g)

When concentrated solution of cupric chloride is taken, chlorine gets liberated at anode, in contrast to a dilute solution where oxygen is liberated. However, when aqueous solution of CuSO_(4) is taken, only oxygen is liberated at anode irrespective of concentration. How do yoy account for this ?

Which metal is isolated from cinnabar?

which of thefollowingrepresentsaprecipitaion reaction ?

Which of the following is not a non-metal ?

Which amongst the following statement is true?

Which of the following correctly describes the magnetic field near a long straight wire?

The spectator ions in the hydrolysis of (NH_(4))_(2) CO_(3) are

White chemical compound become hard on mixing proper quantity of water . It is also used in surgery to maintain joints in a fixed position . Name the chemical compound .

Write word equations and then balanced equations for the reaction taking place when dilute sulphuric acid reacts with zinc granules

Write word equations and then balanced equations for the reaction taking place when dilute sulphuric acid reacts with aluminium powder

What is LPG ?

Which of the following molecules has (have) a triple bond

What happens when (give only balanced equations and write the names of the reactants and products ) Ethyl alcohol is heated with conc. H_2SO_4 at 170^@C

What happens when (give only balanced equations and write the names of the reactants and products )Ethene is allowed to combine with Cl_2 gas.

What happens when (give only balanced equations and write the names of the reactants and products ) Ethene gas is burnt in oxygen.

What happens when (give only balanced equations and write the names of the reactants and products ) Ethyne reacts with chlorine.

What happens when (give only balanced equations and write the names of the reactants and products ) Ethyne and hydrogen combine in the presence of a catalyst.

What happens when (give only balanced equations and write the names of the reactants and products ) Ethyne reacts with excess of bromine.

Using the given part of the periodic table, answer the following questions with reason : (i) Name the element having smallest atomic size. (ii) Write electronic configuration of element E. (iii) Identify the elements which have similar physical and chemical properties as the element Y.

Which functional group is present in carboxylic acid ?

What is covalent radius?

What is the commercial name of calcium sulphate hemihydrate ?

Which of the following d orbitals involved in Sp_(3)d hybridization?

Which of the following metal oxide contains metal in two different valencies ?

The scientist who heated tin in a retort to verify the law of convservation of mass in a chemical reaction

Which among the following is a decomposition reaction ?

Which of the statement about the following reactions is correct ? ZnO + CO to Zn + CO_(2)

Which of the pairs will give displacement reactions ?