This section includes 7 InterviewSolutions, each offering curated multiple-choice questions to sharpen your Current Affairs knowledge and support exam preparation. Choose a topic below to get started.
| 1. |
Argon is formed in meteorites due to cosmic events. Each cosmic event produces one argon atom. If 1.12 xx10^(-3)mL of argon is formed at STP from 10kg of a meteorite, the number of cosmic events that occurred is |
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Answer» `4XX10^(16)` |
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| 2. |
Arenium ion is formed in the reaction. |
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Answer» (I)(IV)(P) |
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| 3. |
Are the oxidation state and covelency of Al in [AlCl (H_2O)_5]^(2+) same ? |
| Answer» Solution :No. The oxidation STATE of Al is + 3 and the covalency is 6. | |
| 4. |
Are the oxidation state and covalency of Al in [AlCl(H_(2)O)_(5)]^(2+) same ? |
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Answer» Solution :No. The oxidation state of Al is `+3 `and the COVALENCY is 6. Because, `+2 = Al + CL + 5 (H_(2) O)` `+2 = x - 1 + 5(0)` ` :. X = +3 = ` oxidation number of Al Al form one covalent bond Cl form one covalent bond and FIVE covalent bond from with `5 H_(2) O`, So total 6 covalent bond is present. |
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| 5. |
The oxidation state and covalency of AI on [AICIH_(2)O_(5)]^(2+) ARE respectively |
| Answer» Solution :No, the OXIDATION STATE of All is +3 and the COVALENCY is 6. | |
| 6. |
Are the oxidation state and covalency of Al in [AICI(H_2O)_5]^(2+)same? |
| Answer» Solution :No, the oxidation STATE of AL is +3 and the COVALENCY is 6. | |
| 7. |
Are theoxidationstateand covalency ofA1 in[A1Cl (H_(2)O)_(6)]^(2+) same ? |
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Answer» Solution :The oxidationstateof `C1 ` is-1 . Letus supposethat oxidation STATEOF a1 is x `:.X - 1 + 6xx 0= + 2" ORX= + 3` Thusthe oxidationstateof ALIS +3 Sincesix ligands(whichcandonate a pairof ELECTRONS ) I.e., `H_(2)O`molecules are attached to thealuminium atom, Thereforeitscovalencyis 6. |
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| 8. |
Are sodium cyanide and potassium cyanide equally poisonous ? |
| Answer» SOLUTION :No. KCN is more POISONOUS than NACN. | |
| 9. |
Are all the five bonds in PCl_(5) equivalent ? Justify. |
| Answer» Solution :`PCl_(5)` has trional bipyramid structure (Fig. 11.35, page 11//134). It has three equatorial BONDS inclined at angle of `120^(@)` and TWO AXIAL bonds inclined at an angle of `90^(@)`. Since two axial P-Cl bonds are repelled by three bond pairs each while three equatorial P-Cl bonds are repelled by two bond pairs each, therefore aixad bonds are longer (240 pm) and HENCE weaker as compared to more stable equatorial bonds (202 pm). Thus, all the five P-Cl bonds in `PCl_(5)` are not EQUIVALENT. | |
| 10. |
are : |
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Answer» METAMER |
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| 11. |
Ar and He are both gases at room temperture. How do the average moleculr velocities (V) of their atoms compare at this temperature? |
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Answer» `V_(He)=10V_(Ar)` |
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| 12. |
Aqueous tension of water depends only on …………..and not on ……………………….. |
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Answer» |
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| 13. |
Aqueous tension of water depends on |
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Answer» the AMOUNT of WATER taken |
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| 15. |
Aqueoussolutionsof twocompoundsM- O- Hand M'- O - Hhavebeenpreparedin twoseparatebeakers. It theelectronegativity ofM= 3.5M= 1.72 ,O = 3.0 andand H=2.1then thesolutions respectively are |
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Answer» acidic , acidic . Inorderwords O - Hbondbecomesweakand readilyionizes toliberate`H^(+)` ThusM-O- Hbehave as an acid. CONVERSELY as theelecronegativityof the metaldecreasesM- Obondbecomesweakandreadilyionizesto LIBERATE `OH^(-)` Thus `M- O- H` behavesas a base. combiningboththe trendsoption (b) is correct. |
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| 16. |
Aqueous tension at 25^@C is given as 23.8 mm, If 1.5 L of nitrogen gas is collected over water at 25^@C and 735 mm Hg, find the mass of dry gas collected in the experiment. |
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Answer» |
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| 17. |
Aqueous solution of KCI is neutral because |
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Answer» `K^(+) ` UNDERGOES hydrolysis |
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| 18. |
Aqueous solution of which of the following compounds is the best conductor of electric current ? |
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Answer» Ammonia, `NH_3` |
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| 20. |
Aqueous solution of sodium carbonate is alkaline due to |
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Answer» HYDROLYSIS of `NA^(+)` |
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| 21. |
Aqueous solution of (P) and (Q) are violet. (P) turns green on oxidatioin while (Q) turns green on reduciton. They may respectively be: |
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Answer» `VCl_(2),CrO_(3)` |
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| 22. |
Aqueous solution of NaHCO_(3) is alkaline |
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Answer» because of CATIONIC HYDROLYSIS |
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| 23. |
Aqueous solution of Na_(2)S_(2)O_(3) on reaction with Cl_(2) with Cl_(2) gives |
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Answer» `Na_(2)S_(4)O_(6)` |
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| 24. |
Aqueous solution of Na_(2)CO_(3) is |
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Answer» Acidic |
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| 25. |
Aqueous solution of H_(3)BO_(3) is treated with salicyclic acid which of the following are incorrect ? |
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Answer» No product is formed because both are acids. `[B(OH)_(4)]^(-)rarr BO_(2)^(-)+2H_(2)O` It is optically resolvable because of assymmetric structure. |
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| 26. |
Aqueous solution of CaCl_(2) is |
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Answer» Acidic |
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| 27. |
Aqueous solution of Ba(OH)_2 is labelled as 0.25M. Calculate the concentrations of OH^(-)and H^(+). |
| Answer» SOLUTION :`(OH^(-)) = 0.5M, [H^(+)]= 2 xx 10^(-15) M` | |
| 28. |
Aqueous solution of BeCl_(2) is |
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Answer» Acidic HENCE the AQUEOUS solution of `BeCl_(2)` is acidic. |
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| 29. |
Aqueous NaOH solution is labelled as 10% by weight mole fraction of the solute in it is |
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Answer» 0.05 |
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| 30. |
{:("Aqueous green soln.of" (A)overset(NH_(4)OH)rarr,"Greenish ppt"(B)),(,""darrNa_(2)O_(2)),("Bright yellow"overset(Aq.Pb(NO_(3))_(2))larr."Orange colour",overset(AcOH)larr"Yellow soln".(C)):} Identify 'D'. |
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Answer» `Na_(2)CrO_(4)` |
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| 31. |
{:("Aqueous green soln.of" (A)overset(NH_(4)OH)rarr,"Greenish ppt"(B)),(,""darrNa_(2)O_(2)),("Bright yellow"overset(Aq.Pb(NO_(3))_(2))larr."Orange colour",overset(AcOH)larr"Yellow soln".(C)):} Identify 'A'. |
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Answer» `AICI_(3)` and `KOH` |
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| 32. |
Aqueous ethanol is labelled as 2 molal. Find the mole fraction of alcohol. |
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Answer» Solution :1000G of WATER HA 2 MOLE of ethanol 55.5 moles of water has 2 mole of ethanol or `X=(m)/(m+55.5)` Mole fraction alcohol`=(2)/(2+55.5)=(2)/(57.5)=0.0348` |
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| 33. |
Aquenous solution of which of the following compounds is the best conductor of electric current ? |
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Answer» Ammonia, `NH_(3)` |
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| 34. |
Applying VSEPR theory, how to predict the shape of IF_7? |
Answer» Solution :`IF_7` : It is an `AB_7` type molecule. This molecules has 7 BOND PAIR of ELECTRONS and no lone pair of elctrons . Due to bond pair-bond pair INTERACTION of elections, `IF_7` has PENTAGONAL bipyramidal shape.
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| 35. |
Applyingbohr.smodelwhenelectronofH atom comesfromn=4to n=2calculate itswavelength |
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Answer» 4866 A |
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| 36. |
Applying Bhor's model when electron in H atom comes from n = 4 to n = 2, calculate the wavelength of the line. In this process, write whether energy is released or absorbed. Also write the range of radiation (R_(H) = 2.18 xx 10^(-18)J, h = 6.63 xx 10^(-34) J) |
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Answer» For H-atom, Z = 1 N = 4 or n= 2 means `n_(2) = 4, n_(1) = 2` Calculate `lamda` |
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| 37. |
Apply the VSEPR model to XeF_(4), which of the following molecular shape is consistent with the model? |
| Answer» Solution :Square planar | |
| 38. |
Application of the heat of combustion ? |
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Answer» Solution :Heat of combination is used (i) to calculateheat of FORMATION (II) to find the calorific VALUE of food and FUEL |
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| 40. |
Apart from tetrahedral geometry, another possible geometry for CH_(4) is square planar with the four H atoms at the corners of the square and the O atom at its centre. Explain why CH_(4) is not square planar ? |
Answer» SOLUTION :Experimentally dipole moment of `CH_(4)` is `MU` = ZERO so, `CH_4)` molecule is NONPOLAR.
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| 41. |
Apart from tetrahedral geometry, another possible geometry forCH_(4) is square planar with four H atoms at the corners of the square and the C atom as its centre . Explain why CH_(4)is not square planar . |
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Answer» Solution :Electronic configuration of C-atom is ` 2S^(2) 2s^(2) 2p_(x)^(1) 2p_(y)^(1)` in the ground state and ` 1s^(2) 2s^(1) 2p_(x) ^(1) 2p_(y)^(1) 2p_(z)^(1)` in The excited state . Hence,it undergoes ` sp^(3)`hybridisation which gives a tetrahedral shape. For square Plana, the hybridisation required is `dsp^(2)`which is not possible for C-atom in `CH_(4)` . ALSO according to VSEPR theory ,if ` CH_(4)` wereplanar, the bond angle would be `90^(@)`. for tetrahedral structure , the bond angle is ` 109^(@) 28`'. Thus ,in the square planer structure , repulsions between the bond pairs would be more and , THEREFORE , the stability will be less. |
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| 42. |
Apart from tetrahedral geometry, another possible geometry for CH_(4) isSquare planar With four H atoms at the corners of the square and C atom at its centre. Explain why CH_(4) is not square planar? |
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Answer» SOLUTION :ELECTRONIC configuration of carbon atom: C : `SIGMA1S^(2)2s^(2)2p^(2)` In the excited state, the orbital picture of carbon can be represented as: Hence. carbon atom undergoes `sp^(3)` hybridisation in `CH_(4)` molecule and takes tetrahedral shape. ror a SQUARE planar shape, the hybridisation of the central atom has to be `dsp^(3)`. However, an atom of carbon does not have d-orbitals to undergo `dsp^(3)` hybridisation. Hence, the structure of `CH_(4)`is tetrahedral. |
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| 43. |
Aoverset(O_(3))underset(Zn//H_(2)O)to2 Identify A and name the reaction |
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Answer»
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| 44. |
A(OH)_(2)is a partially soluble substance and its K_(sp)value is 4 xx 10^(-12) . Which of the following statement is / are correct ? |
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Answer» The solubility is unaffected by pH of the MEDIUM ` "" S "" 2S ` ` 4 xx 1 0^(_12) =4S ^(3) rArr S =1 0 ^(_4) M` ` [OH^(-)] = 2 xx 10^(_4)M` ` pOH =4- log 2 = 3.7 rArr pH =10.3` |
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| 45. |
A(OH)_2is a partially soluble substance and itsK_(sp) "value is " 4xx10 ^(-12)Which of the following statement is/are correct ? |
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Answer» The solubility is unaffected by pH of the medium ` "" S "" 2S ` ` 4 xx 1 0^(_12) =4S ^(3) rArr S =1 0 ^(_4) M` ` [OH^(-)] = 2 xx 10^(_4)M` ` pOH =4- log 2 = 3.7 rArr pH =10.3` |
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| 46. |
Anything that influences the valence electrons will affect the chemistry of the element. Which one of the following factors does not affect the valence shell ? |
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Answer» VALENCE principal quantum number (n) |
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| 47. |
Anything which separates the system from its surroundings is called ____ |
| Answer» SOLUTION :BOUNDARY | |
| 48. |
Anything thatinfluencesthe valenceelectronswill affectthe chemistryof theelement . Whichoneof the followingfactors does not affectthe valenceshell ?(a ) Valenceprincipal quantumnumber (n )( b)Nuclear charge (Z) ( c)nuclear mass(d ) Numberof coreelectrons. |
| Answer» SOLUTION :Nuclearmass does not affect THEVALENCE shellbecausenucleus consists ofprotons and neutrons. Whereas proton i.e.,nuclearchargeaffects thevalenceshellbut neutronsdo not. Thusoption ( C)is WRONG. | |
| 49. |
Any alkyl bromide (a) reacts with sodium in ether to form 4,5 -diethylocatane the compound |
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Answer» `CH_(3)(CH_(2))BR` |
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| 50. |
Anunknown compound 'A' has a molecular formula of C_(4)H_(6) when 'A' is treated with an excess of Br_(2) a new substance 'B' with formula C_(4)H_(6)Br_(2) is formed. A forms a white precipitate with ammonical silver nitrate solution 'A' may be |
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Answer» BUTYNE |
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