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Engineering
174 Views   |  

The Number of Carbon atoms per unit cell of diamond unit cell is :

  • Option 1)

    8

  • Option 2)

    6

  • Option 3)

    1

  • Option 4)

    4

 
As we learnt in  Diamond unit all is FCC with 4 atoms additionally bonded tetrahedrally which have full contribution to the all.  So, no.of atoms                               Option 1) 8 this option is correct Option 2) 6 this option is incorrect Option 3) 1 this option is incorrect Option 4) 4 this option is incorrect
Engineering
102 Views   |  

In Castner-Kellner cell for production of sodium hydroxide:

  • Option 1)

    Brine is electrolyzed with Pt electrodes

  • Option 2)

    Brine is electrolyzed using graphite electrodes

  • Option 3)

    Molten sodium chloride is electrolyzed

  • Option 4)

    Sodium amalgam is formed at mercury cathode

 
As we learnt in Preparation of NaOH by castner-Kellner cell - Also known as mercury cathode process by electrolysis of aq.solution of brine cathode:   Anode: - wherein Cell comprises of three compartments Outer compartment:Brine solution is electrolysed Central compartment: 2% NaOH solution and     In the Castner Kellner cell,  At cathode,  At anode,  Sodium Amalgam is formed at...
Engineering
120 Views   |  

What is the density of N_{2} gas at 227^{o}C and 5.00 atm pressure? (R=0.0821 atm K^{-1} mol^{-1})

  • Option 1)

    0.29 g/ml

  • Option 2)

    1.40 g/ml

  • Option 3)

    2.81 g/ml

  • Option 4)

    3.41 g/ml

 
  Ideal Gas Law - - wherein P - Pressure V - Volume n - No. of Moles R - Gas Constant T - Temperature     Ideal Gas Law in terms of density - - wherein where d - density of gas P - Pressure R - Gas Constant T - Temperature M - Molar Mass      from ideal gas equation  Pv=nRT or PM=RT = Option 1) 0.29 g/ml This option is incorrect  Option 2) 1.40 g/ml This option is incorrect  Option 3) 2.81...
Engineering
256 Views   |  

Which condition is not satisfied by an ideal solution?

  • Option 1)

    \Delta _{mix}H=0

  • Option 2)

    \Delta _{mix}V=0

  • Option 3)

    \Delta _{mix}S=0

  • Option 4)

    Obeyance to Raoult's Law

 
As learnt Condition of ideality - Interaction between A - A; B - B are similar to A - B Interactions. eg. Hexane + Heptone Benzene + Toluere - wherein       Conditions for ideality for a solution are: Also, an ideal solution always Raoult's Law Option 1) This option is incorrect Option 2) This option is incorrect Option 3) This option is correct Option 4) Obeyance to Raoult's Law This...
Engineering
115 Views   |  

Which statement is wrong?

  • Option 1)

    Feldspars are not aluminosilicates

  • Option 2)

    Beryl is an example of cyclic silicate

  • Option 3)

    Mg_{2}SiO_{4}  is orthosilicate

  • Option 4)

    Basic structural unit in silicates is the SiO_{4}  tetrahedron

 
As we learned in concept Ores of Aluminium - Bauxite - Cryolite - Felspar - Kaolinite - Mica - Corumdum - Diaspore - Alunite oralum stone - -   Feldspars (KAISi3O8 - NaAlSi3O8 - Ca Al2 Si3O8 ) are a group of aluminosilicates. therefore, solution is 1. Option 1) Feldspars are not aluminosilicates correct Option 2) Beryl is an example of cyclic silicate incorrect Option 3)   is...
Engineering
99 Views   |  

Which of the following structure is similar to graphite?

  • Option 1)

    B

  • Option 2)

    B_{4}C

  • Option 3)

    B_{2}H_{6}

  • Option 4)

    BN

 
As we learnt in Reactivity of boron towards air - Amorphous boron on heating in air form B2O3 (acidic) with dinitrogen they form nitrides - wherein       Option 1) B Incorrect Option 2) Incorrect Option 3) Incorrect Option 4) BN Correct
Engineering
100 Views   |  

Three thermochemical equations are given below

(i) C_{\left ( graphite \right )}+O_{2}\left ( g \right )\rightarrow CO_{2}\left ( g \right );

                                                             \Delta _{r} H^{o}=xkJmol^{-1}

(ii) C_{\left ( graphite \right )}+\frac{1}{2}O_{2}\left ( g \right )\rightarrow CO\left ( g \right );

                                                               \Delta _{r} H^{o}=ykJmol^{-1}

(iii) CO\left ( g \right )\frac{1}{2}O_{2}\left ( g \right )\rightarrow CO_{2}\left ( g \right );

                                                          \Delta _{r} H^{o}=zkJmol^{-1}

Based on the above equations, find out which of the relationship given below is correct?

  • Option 1)

    x=y-z

  • Option 2)

    z=x+y

  • Option 3)

    x=y+z

  • Option 4)

    y=2z-x

 
As we learnt in Hess's Law - The total amount of heat change in a chemical reaction is the same whether the reaction is carried  out in one or several steps by one or more methods. - wherein    According to Hest law, equation  (i) is sum of equation (ii) and (iii)   Option 1) x=y-z This option is incorrect  Option 2) z=x+y This option is incorrect  Option 3) x=y+z This option is...
Engineering
143 Views   |  

One coolie takes 1 minute to raise a suitcase through a height of 2 m but the second coolie takes 30 s to raise the same suitcase to the same height. The powers of two coolies are in the ratio of

  • Option 1)

    1:2

  • Option 2)

    1:3

  • Option 3)

    2:1

  • Option 4)

    3:1

 
As discussed in Power - Rate of doing work -     Work done = mgh in both case Option 1) 1:2 This solution is correct Option 2) 1:3 This solution is incorrect Option 3) 2:1 This solution is incorrect Option 4) 3:1 This solution is incorrect
Engineering
99 Views   |  

A person holding a rifle (mass of person and rifle together is 100 kg) stands on a smooth surface and fires 10 shots horizontally , in 5 s. Each bullet has a mass of 10 g with a muzzle velocity of 800ms^{-1}. The final velocity acquired by the person and the average force exerted on the person are

  • Option 1)

    -1.6ms^{-1};\: 8 N

  • Option 2)

    -0.08ms^{-1}; 16 N

  • Option 3)

    -0.8ms^{-1}; 8 N

  • Option 4)

    -1.6ms^{-1};16 N

 
As discussed in  Work Energy Theorem - Work done by all the forces acting on a particle equal to change in kinetic energy. -     From work energy theorem Option 1) This solution is incorrect Option 2) This solution is incorrect Option 3) This solution is correct Option 4) This solution is incorrect
Engineering
103 Views   |  

Which is the strongest acid in the following:

  • Option 1)

    HClO_{3}

  • Option 2)

    HClO_{4}

  • Option 3)

    H_{2}SO_{3}

  • Option 4)

    H_{2}SO_{4}

 
As learnt in Acidic strength of oxyacids - HClO4>HCIO3>HCIO2>HCIO - wherein Acidic strenght  electronegativity of central atom    acidity  oxidation state of central atom and greater the delocalization of negative charge on the union, higher will be the acidity as greater delocalization makes the conjugate base more stable. Option 1) This solution is incorrect Option 2) This solution is...
Engineering
358 Views   |  

A particle with total energy E is moving in a potential energy region U (x). Motion of the particle is restricted to the region when

  • Option 1)

    U (x) > E

  • Option 2)

    U(x) <E

  • Option 3)

    U (x) =0

  • Option 4)

    U(x) \leq E

 
As discussed in If only conservative forces act on a system, total mechnical energy remains constant - -    As the particle is moving in a potential energy region Total Energy = F = K.E + P.E                           =  Option 1) U (x) > E This solution is incorrect Option 2) U(x) <E This solution is incorrect Option 3) U (x) =0 This solution is incorrect Option 4) U(x) E This solution...
Engineering
96 Views   |  

Identify the incorrect statement, regarding the molecule XeO_{4}:

  • Option 1)

    XeO_{4} molecule is tetrahedral

  • Option 2)

    XeO_{4} molecule is square planar

  • Option 3)

    There are four p\pi -d\pi bonds

  • Option 4)

    There are four sp^{3}-p, \sigma bonds

 
As we learned in concept Oxide of Xenon -   - wherein Due to high electronegativity of oxygen it form coumpound with Xe     is hybridized and has tetrahedral shape and not square planer Option 1)  molecule is tetrahedral This is incorrect option Option 2) molecule is square planar This is correct option Option 3) There are four  bonds This is incorrect option Option 4) There are four ...
Engineering
178 Views   |  

What is the htbridisation state of benzyl carbonium ion  

  • Option 1)

    sp^{3}

  • Option 2)

    sp^{2}

  • Option 3)

    spd^{2}

  • Option 4)

    sp^{2}d

 
As we learnt in Carbocation - Those chemical species having trivalent carbon and bearing positive charge. - wherein    There is a double bond character at carbonium ion due to resonance, hence its hybridsation is sp2.   Option 1) Incorrect Option 2) Correct Option 3) Incorrect Option 4) Incorrect
Engineering
123 Views   |  

Homolytic fission of the following alkanes forms free radicals 

CH_{3}-CH_{3},CH_{3}-CH_{2}-CH_{3},\left ( CH_{3} \right )_{2}CH-CH_{3},CH_{3}-CH_{2}-CH\left ( CH_{3} \right )_{2}. 

Increasing order of stability of the radicals is

  • Option 1)

    \left ( CH_{3} \right )_{3}\dot{C}<\left ( CH_{3} \right )_{2}\dot{C}-CH_{2}CH_{3}<CH_{3}-\dot{C} H-CH_{3}<CH_{3}-\dot{C}H_{2}

  • Option 2)

    \left ( \dot{C}H_{3} \right )_{2}\dot{C}-CH_{2}CH_{3}<CH_{3}-\dot{C}H-CH_{3}<CH_{3}-\dot{C}H_{2}<\left ( CH_{3} \right )_{3}\dot{C}

  • Option 3)

    CH_{3}-\dot{C}H_{2}<CH_{3}-\dot{C}H-CH_{3}<\left ( CH_{3} \right )_{2}\dot{C}-CH_{2}-CH_{3}<\left ( CH_{3} \right )_{3}\dot{C}

  • Option 4)

    CH_{3}-\dot{C}H_{2}<CH_{3}-\dot{C}H-CH_{3}<\left ( CH_{3} \right )_{3}\dot{C}<\left ( CH_{3} \right )_{2}\dot{C}-CH_{2}CH_{3}

 
As we learnt in Stability of alkyl free radical - Electron donating group stabilises alkyl free radicals and withdrawing group destabilises alkyl free radicals. - wherein    More is the number of hyper conjugative structure, the greater is the stability.   Option 1) Incorrect Option 2) Incorrect Option 3) Correct Option 4) Incorrect
Engineering
103 Views   |  

Arrange the following in increasing order of stability

(A) \left ( CH_{3} \right )_{2}\overset {\bigoplus }{C}-CH_{2}CH_{3}

(B) }\left ( CH_{3} \right )_{3}-\overset {\bigoplus }{C}

(C) \left ( CH_{3} \right )_{2}-\overset {\bigoplus }{C}H

(D) \left ( CH_{3} \right )-\overset {\bigoplus }{C}H_{2}

(E) \overset {\bigoplus }{C}H_{3}

  • Option 1)

    E < D < C < B < A

  • Option 2)

    E < D < C < A < B

  • Option 3)

    D < E < C < A < B

  • Option 4)

    A < E < D < C < B

 
As we learnt in Stability of Carbocation - Electron donating group stabilises carbocation - wherein Inductive effect Hyper Conjugation resonance    Greater the number of electron donating alkyl group (+I) effect, greater is the stability of carbocation + I effect is in the order. E < D < C < A < B   Option 1) E < D < C < B < A Incorrect Option 2) E < D < C < A < B Correct Option 3) D < E < C...
Engineering
349 Views   |  

Nitrobenzene on reaction with conc. HNO3/H2SO4 at 80 - 100°C forms which one of the following products?

  • Option 1)

    1,3 - Dinitrobenzene

  • Option 2)

    1,4 - Dinitrobenzene

  • Option 3)

    1,2,4 - Trinitrobenzene

  • Option 4)

    1,2 - Dinitrobenzene

 
As we learnt in Preparation of Nitrobenzene medium - It is prepared by nitration of benzene by nitrating mixture conc. HNO3 and conc. H2SO4. At     - wherein       Option 1) 1,3 - Dinitrobenzene Correct Option 2) 1,4 - Dinitrobenzene Incorrect Option 3) 1,2,4 - Trinitrobenzene Incorrect Option 4) 1,2 - Dinitrobenzene Incorrect
Engineering
97 Views   |  

On hydrolysis of a "compound", two compounds are obtained. One of which on treatment with sodium nitrite and hydrochloric acid gives a product which does not respond to iodoform test. The second one reduces Tollen's reagent and Fehling's solution. The "compound" is

  • Option 1)

    CH3CH2CH2CON(CH3)2

  • Option 2)

    CH3CH2CH2NC

  • Option 3)

    CH3CH2CH2CN

  • Option 4)

    CH3CH2CH2ON=O

 
As we learnt in  Hydrolysis of isocyanides - Alkyl isocyanide are hydrolysed to an amine and formic acid by dilute acid, but not hydrolysed by Alkalis due to negatively charged carbon which resists the attack of ions. - wherein   HCOOH - Reduces Tollen's reagent and Fehling's solution   (II) Option 1) CH3CH2CH2CON(CH3)2 This is incorrect option Option 2) CH3CH2CH2NC This is correct...
Engineering
130 Views   |  

Some reactions of amines are given. Which one is not correct?

  • Option 1)

    (CH3)2NH+NaNO2+HCl —> (CH3)2N-N=O

  • Option 2)

  • Option 3)

    CH3CH2NH2+HNO2 —> CH3CH2OH + N2

  • Option 4)

    CH3NH2+C6H5SO2Cl —> CH3NHSO2C6H5

 
As discussed in Reaction of tertiary arylamines with HNO2 - tertiary arylamines react with nitrous acid to form  P - nitroso aromatic compounds. - wherein    In option 2, wrong product is formed. Option 1) (CH3)2NH+NaNO2+HCl —> (CH3)2N-N=O This option is incorrect. Option 2) This option is correct. Option 3) CH3CH2NH2+HNO2 —> CH3CH2OH + N2 This option is incorrect. Option...
Engineering
101 Views   |  

Which one of the following molecules contains no \pi bond?

  • Option 1)

    H_{2}O

  • Option 2)

    SO_{2}

  • Option 3)

    NO_{2}

  • Option 4)

    CO_{2}

 
As we learnt in  Pi bond - This type of bond is formed by sidewise or lateral over lapping of two half filled atomic orbitals. - wherein     It has no   bond as H does not have any vacant orbitals for a bond Option 1) THis is correct option Option 2) This is incorrect option Option 3) This is incorrect option Option 4) This is incorrect option
Engineering
95 Views   |  

Which of the following is electron-deficient?

  • Option 1)

    (SiH3)2

  • Option 2)

    (BH3)2

  • Option 3)

    PH3

  • Option 4)

    (CH3)2

 
As we learnt in  Octet Rule - Atoms form chemical bond in order to complete their octet i.e eight electrons in their valence shell -     is called diborane. In this compound, the octet for B is incomplete which is why it dimerizes. So is electron defincient. Option 1) (SiH3)2 This is incorrect option Option 2) (BH3)2 This is correct option Option 3) PH3 This is incorrect option Option...
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