8881 + Interview Questions in Chemistry in Class 10 Page 75 InterviewSolution

3701.	Position of isotopes in the Mendeleev's and the Modem Periodic table.
Answer» Solution :(i) Different atoms of the same element having same ATOMIC number but different atomic mass number are called isotopes. (ii) Isotopes were discovered long time after Mendeleev put forth the periodic table. (iii) As isotopes have the same chemical properties but different atomic masses, a challenge was posed in placing them in Mendeleev.s periodic table. (iv) Based on chemical properties, they were to be placed in same group, while based on atomic masses they were to be placed in different groups. (V) Hence, there was no definite place for isotopes. (vi) This ANOMALY arose in Mendeleev.s periodic table because the elements were arranged in an increasing order of their atomic masses. (vii) In 1913 AD., Henry Moseley revealed that atomic number is a more fundamental PROPERTY of an element than its atomic mass. (viii) Hence, he MODIFIED Mendeleev.s Periodic Table and arranged the elements in an increasing order of their atomic number in the Modem Periodic Table. (ix) By doing so, the anomaly of Mendeleev.s Periodic Table regarding isotopes was removed. (x) Therefore, in the Modem Periodic Table the isotopes could be placed in the same group and the radioactive isotopes were placed in two separate series below at the bottom of the periodic table.

Discussion

3702.	Polymer used in marking floor tiles is
Answer» teflon POLYPROPYLENE POLYVINYL CHLORIDE buta-1, 3-diene ANSWER :C

Discussion

3703.	Plumbous ion is represented as
Answer» `Pb^(+2)` `Pb^(+4)` `Pb^(+3)` `Pb^(+1)` Solution :Suffix 'ous' denotes lower valency exhibited by the metal, when COMPARED with suffix 'ic', which denotes HIGHER valency of the metal. Hence, plumbous is `Pb^(+2)`.

Discussion

3704.	Plaster of Paris should be stored in _________ containers.
Answer» Solution :MOISTURE-proof. Moisture reacts with PLASTER of PARIS to form gypsum.

Discussion

3705.	Plaster of Paris should be stored in a moisture-proof container. Explain why?
Answer» Solution :Plaster of Paris REACTS with MOISTURE to form GYPSUM and SETS to a HARD mass.

Discussion

3706.	Plaster of Paris should be stored in a moisture-proof container. Explain why ?
Answer» Solution :This is because in presence of moisture, plaster of PARIS SETS to give a HARD mass. `underset("Plaster of Paris")(CaSO_4 . 1//2 H_2O ) + 3//2 H_2O to underset("(Hard mass)")(CaSO_4. 2H_2O)`

Discussion

3707.	Plaster of Paris is obtained by heating
Answer» gypsum limestone sodium carbonate calcium sulphate SOLUTION :`UNDERSET("gypsum")(2CaSO_(4).2H_(2)O)overset(100^(@)C)to underset("PLASTER of paris")((CaSO_(4))_(2)3overset(+)H_(2)O)`

Discussion

3708.	Plants lose water by a process known as
Answer» PHOTOSYNTHESIS RESPIRATION TRANSPIRATION afforestion ANSWER :C

Discussion

3709.	Piyush is a student of class 10. His teacher was teaching the type of chemical reactions in the class. Piyush was aksed to carry out the reaction of electrolysis of water in the laboratory. Piyush set up the complete apparatus for the electrolysis of water. He took pure water (distilled water) to carry out this reaction. When Piyush passed electric current through this water for a considerable time even then no chemical reaction took place. Piyush told this problem to his classmate Arjun. Arjun thought over the problem and asked Piyush to add a little of a certain substance into pure water before passing electric current through it. When electric current was passed thorugh water after adding a little of this substance then a chemical reaction took place to form two gases X and Y. The volume of gas X collected over one of the electrodes was 8mL whreas the volume of gas Y collected over the other electrode was 16mL (a) Why no chemical reaction took place when electric current was passed thorugh pure water? (b) What substance was added in little quantity to pure water before passing electric current again? (c) How did theaddition of little of this substance help in the electrolysis of water? (d) What is gas X? Over which electrode is it collected? (e) What is gas Y? Over which electrode is it collected? (f) What type of chemical reaction is demonstrated by this experiment ? Why? (g) What values are displayed by Arjun in this episode?
Answer» Solution :(a) because pure water (or distilled water) is a non conductor of electricity. (b) Sulphuric acid. (c) Sulphuric acid is an electrolyte. The addition of a LITTLE of sulphuric acid made water a good conductor of electricity. (The water containing a little of sulphuric acid is CALLED acidified water). (d) The gas `X` is oxygen. It is collected over the positive electrode (called ANODE). (e) The gas `Y` is hydrogen. It is collected over the negative electrode (called cathode). (f) This experiment shows a decomposition reaction. In his decomposition reaction water decompose into two constituents : oxygen and hydrogen. (g) The VALUES displayed by Arjun in this episode are: (i) Awareness (or knowledge) that pure water is a non-conductor of electricity which can be made a god conductor by adding a little of dilute sulphuric acid, and (II) Helping nature.

Discussion

3710.	Pics out the correct ionic radii in increasingorder for the following species -Na , Cl, Na^(+) , Cl^(-)
Answer» NAGT Clgt `NA^(+)` GT CL Cl gt Na gt `Na^(+)`gt `Cl^(-)` `Cl^(-)` gt Nagt `Na^(+)` gt Cl Clgt `Na^(+)` LT `Cl^(-)`lt Na Answer :D

Discussion

3711.	Pick the correct sentence from the following
Answer» A mixture has a fixed melting point and boiling point. A COMPOUND is FORMED by the COMBINATION of two or more elements in a definite ratio by mass. A mixture is ALWAYS heterogenous . A mixture is always homogeneous Answer :B

Discussion

3712.	Pick the correct order on decreasin trend of atomic size
Answer» `MG,Mg^(+),Mg^(2+)` `Mg^(+),Mg^(2+),Mg ` `Mg^(2+),Mg^(+),Mg` `Mg^(2+),Mg,Mg^(+)` ANSWER :C

Discussion

3713.	Pick out the unsaturated compound form the following.
Answer» `CH_(3)-CH_(2)-CH_(3)` `CH_(3)-CH=CH_(2)` `CH_(3)-C-=CH` both (B) and (c ) ANSWER :D

Discussion

3714.	Pick out the saturated compound form the following.
Answer» PROPANE propene propyne butene Answer :A

Discussion

3715.	Pickoutthe isotopesamongthefollowingpairs
Answer» `""_(6) C^(13), ""_(7)N^(14)` `""_(18) Ar^(40), ""_(20)Ca^(40)` `""_(6) C^(12), C_(6)^(14)` `""_(5) B^(12), ""_(6)C^(13)` Answer :C

Discussion

3716.	Pickout theheteronuclearpolyatomicmoleculesamongthefollowingandclassifythembasedon theiratomicity . C_(6)H_(12) ,O_(6 )P_(4) ,Cl _(2) ,NH_(3),HCI,N_(2)CO_(3),O_(3), NH_(4)Cl ,CaCO _(3), O_(2),SO_(2)
Answer» SOLUTION :

Discussion

3717.	Pick out the functional group for alcohol.
Answer» `- CHO` `- COOH` `- OH` `- OR` ANSWER :C

Discussion

3718.	Pick out the alkane which differs from the other members of the group
Answer» 2,2-dimethyl PROPANE PENTANE 3-methyl BUTANE 2,2-dimethyl butane Solution :2,2-dimethyl propane, pentane and 3-methyl butane are STRUCTURAL ISOMERS.

Discussion

3719.	Pickout:compound+ elementtocompoundtypeof combinationreaction
Answer» `PCl_(5)toPCI_3 +Cl_2` `Mg+O_2 to 2MgO` `PCI_3 Cl_2 toPCl_(5)` `2Na+Cl_(2) to2NaCl` ANSWER :C

Discussion

3720.	Pickout a chemicalreaction whichis notfeasible
Answer» `2NaCl to2Na+Cl_(2)` `2NaCl +Fto2NaF+Cl_(2)` `2Naf+Cl_(2) to2NaCl+F` `NaOH+HCl to NACL +_(2)O` ANSWER :C

Discussion

3721.	Phototropism is caused to differential distribution of
Answer» Abscisic acid Gibberellin Cytokinin Auxin Answer :D

Discussion

3722.	Photolysis is a decomposition reaction caused by……
Answer» heat<BR>Electricity LIGHT Mechanical energy Solution :`2AgBr_((s))OVERSET("Light")to2Ag_((s))+Br_(2(G))`

Discussion

3723.	Photochemical reactions are carried out in the presence of
Answer» HEAT ELECTRICITY LIGHT air Answer :C

Discussion

3724.	Phosphorus is the eighth element after nitrogen.
Answer» ANSWER :FALSE

Discussion

3725.	Phosphorusmoleculeis a________.
Answer» SOLUTION :HOMO polyatomicmolecule

Discussion

3726.	Phosphorous can form PCl_(5) molecule in the excited state of phosphorous atom. But the formation of PH_(5) is not possible in the same state. Account for this.
Answer» SOLUTION :(i) VALENCE electronic CONFIGURATION of hydrogen and chlorine (ii) type of hybridisation in `PCl_(5)` (iii) comparison of electronegativities between hydrogen and chlorine (iv)the difference between the ENERGIES of OVERLAPPING orbitals

Discussion

3727.	Phosphorous can form PCl_(5) molecule in the excited state of phosphorous atom. But the formation of PH_(5) is not possible in the same state. How do you account for this?
Answer» Solution :The valence electronic configuration of phosphorous is `3s^(2)3p^(3)`. THOUGH there are only three half-filled orbitals for bonding, in the excited state five half-filled orbitals are AVAILABLE for bond formation. Among these five orbitals, three are 'p-' orbitals and two are 'd-' orbitals. These orbitals overlap with the half-filled '3p'orbitals of five chlorine atoms forming `PCl_(5)` molecule. Such a situation is not POSSIBLE with hydrogen atoms SINCE there is wide VARIATION in energies between '3d' orbitals of phosphorous and '1s' orbitals of hydrogen.

Discussion

3728.	Phosphorous and sulphur are monoatomic molecules.
Answer» Solution :Correct STATEMENT : PHOSPHOROUS and sulphur are POLYATOMIC MOLECULES.

Discussion

3729.	Ph(OH)Cl is an acid salt.
Answer» SOLUTION :NA

Discussion

3730.	Phenolphthalein is a/an ____ indicator
Answer» ANSWER :ACIDIC

Discussion

3731.	pH scale was introduced by…………and the pH of the solution is 7,it is a………..solution.
Answer» SOLUTION :S.P.L. Soerenson,NEUTRAL

Discussion

3732.	pH of water is 7 so it is
Answer» acidic neutral BASIC NONE of these Answer :B

Discussion

3733.	pH of tomato juice is 4, that means it is
Answer» basic acidic neutral none of these Answer :B

Discussion

3734.	pHofstomachfluidis approximately2.0
Answer» ANSWER :TRUE

Discussion

3735.	pH of milk ofmagnesia is……..
Answer» 10 15 14 10.5 Answer :A

Discussion

3736.	pH of human blood lies between:
Answer» 7.35 - 7.45 8.35 – 8.45 LESS than 7 More than 8. Solution :7.35 - 7.45

Discussion

3737.	pH of ammonium chloride (NH_(4)CI) or copper sulphate (CuSO_(4)) solution be
Answer» 7 `GT 7` `LT 7` 0 Answer :3

Discussion

3738.	pHnotationwas devisedby thethe ______.
Answer» SOLUTION :SORENSEN

Discussion

3739.	pH=-log_(10)[H^(+)].The pH of a solution containing hyfrogen ion concentration of 0.001 M solution is …………
Answer» 3 11 14 15 Answer :C

Discussion

3740.	pH is……..
Answer» SOLUTION :`-log_(10)[H^(+)]`

Discussion

3741.	pH has a great importance in our daily life. Explain by giving three examples.
Answer»

Discussion

3742.	"pH has a great importance in our daily life". Explain by giving three examples.
Answer» Solution :(a) The acidic pH of our STOMACH aids in digestion. (b) Specific pH of the soil helps in the healthy growth of plants. (C ) If the pH of the teeth is lower than 5.5., the TOOTH enamel gets corroded and causes tooth decay (d) Bee sting leaves an acid causing pain and irritation. APPLYING a mild BASE in that area provides relief due to the neutralisation effect of the acid.

Discussion

3743.	Petroleum is a renewable naturalf resource.
Answer» ANSWER :F

Discussion

3744.	Permanent magnets can be made from
Answer» Ni steel cobalt steel STAINLESS steel wrought IRON Answer :D

Discussion

3745.	Periodicalremovalof oneof theproductsofa reversiblereactionincreases the yield .
Answer» ANSWER :TRUE

Discussion

3746.	Periods
Answer» Solution :The HORIZONTAL ROW s of elements in the PERIODICTABLE are CALLED periods .

Discussion

3747.	The percentage of nitrogen in urea is:
Answer» ANSWER :46.67

Discussion

3748.	People use a variety of methods to wash clothes. Usually after adding the soap, they 'beat' the clothes on a stone, or beat it with a paddle, scrub with a brush or the mixture is agitated in a washing machine. Why is agitation necessary to get clean clothes ?
Answer» SOLUTION :Soap decreases the surface tension of water. When the soap is applied to any dirty clothes or on STAINS, the non-polar tail containing hydrocarbon part is ATTRACTED towards the MOLECULE of DIRT, oil or grease, while the polar tail part is attracted towards water. Thus, micelles are formed. Hence, to remove the micelles from the surface of the clothes, agaitation of clothes is necesary.

Discussion

3749.	People use a variety of methods to wash clothes . Usually after adding the soap, they beat the clothes on a stone, or beat them with a paddle , scrub with a brush , or the mixture is agitated in a washing machine . Why is agitation necessary to get clean clothes?
Answer» SOLUTION :To DETACH the micelle from the surface of cloth, FORMED when soap molecules get attracted to the DIRT.

Discussion

3750.	People use a variety of methods to wash clothes. Usually after adding the soap, they 'beat' the clothes on a stone, or beat it with a paddle, scrub with a brush or the mixture is agitated in a washing machine. Why is agitationnecessary to get clean clothes?
Answer» Solution :AGITATION is necessary to get clean CLOTHES because the soap micelles which entrap OILY or greasy particles on the surface of dirty cloth have to be REMOVED from its surface. When the wetted cloth in soap solution is agitated, the micelles containing oily or greasy dirt particles get removed from the surface of dirty clothand GO into the water and the dirty cloth gets cleaned.

Discussion

Explore topic-wise InterviewSolutions in .

Position of isotopes in the Mendeleev's and the Modem Periodic table.

Polymer used in marking floor tiles is

Plumbous ion is represented as

Plaster of Paris should be stored in _________ containers.

Plaster of Paris should be stored in a moisture-proof container. Explain why?

Plaster of Paris should be stored in a moisture-proof container. Explain why ?

Plaster of Paris is obtained by heating

Plants lose water by a process known as

Pics out the correct ionic radii in increasingorder for the following species -Na , Cl, Na^(+) , Cl^(-)

Pick the correct sentence from the following

Pick the correct order on decreasin trend of atomic size

Pick out the unsaturated compound form the following.

Pick out the saturated compound form the following.

Pickoutthe isotopesamongthefollowingpairs

Pickout theheteronuclearpolyatomicmoleculesamongthefollowingandclassifythembasedon theiratomicity . C_(6)H_(12) ,O_(6 )P_(4) ,Cl _(2) ,NH_(3),HCI,N_(2)CO_(3),O_(3), NH_(4)Cl ,CaCO _(3), O_(2),SO_(2)

Pick out the functional group for alcohol.

Pick out the alkane which differs from the other members of the group

Pickout:compound+ elementtocompoundtypeof combinationreaction

Pickout a chemicalreaction whichis notfeasible

Phototropism is caused to differential distribution of

Photolysis is a decomposition reaction caused by……

Photochemical reactions are carried out in the presence of

Phosphorus is the eighth element after nitrogen.

Phosphorusmoleculeis a________.

Phosphorous can form PCl_(5) molecule in the excited state of phosphorous atom. But the formation of PH_(5) is not possible in the same state. Account for this.

Phosphorous can form PCl_(5) molecule in the excited state of phosphorous atom. But the formation of PH_(5) is not possible in the same state. How do you account for this?

Phosphorous and sulphur are monoatomic molecules.

Ph(OH)Cl is an acid salt.

Phenolphthalein is a/an ____ indicator

pH scale was introduced by…………and the pH of the solution is 7,it is a………..solution.

pH of water is 7 so it is

pH of tomato juice is 4, that means it is

pHofstomachfluidis approximately2.0

pH of milk ofmagnesia is……..

pH of human blood lies between:

pH of ammonium chloride (NH_(4)CI) or copper sulphate (CuSO_(4)) solution be

pHnotationwas devisedby thethe ______.

pH=-log_(10)[H^(+)].The pH of a solution containing hyfrogen ion concentration of 0.001 M solution is …………

pH is……..

pH has a great importance in our daily life. Explain by giving three examples.

"pH has a great importance in our daily life". Explain by giving three examples.

Petroleum is a renewable naturalf resource.

Permanent magnets can be made from

Periodicalremovalof oneof theproductsofa reversiblereactionincreases the yield .

Periods

The percentage of nitrogen in urea is:

People use a variety of methods to wash clothes. Usually after adding the soap, they 'beat' the clothes on a stone, or beat it with a paddle, scrub with a brush or the mixture is agitated in a washing machine. Why is agitation necessary to get clean clothes ?

People use a variety of methods to wash clothes . Usually after adding the soap, they beat the clothes on a stone, or beat them with a paddle , scrub with a brush , or the mixture is agitated in a washing machine . Why is agitation necessary to get clean clothes?

People use a variety of methods to wash clothes. Usually after adding the soap, they 'beat' the clothes on a stone, or beat it with a paddle, scrub with a brush or the mixture is agitated in a washing machine. Why is agitationnecessary to get clean clothes?