Chemistry pu 2nd year Key answers 2019- Karnataka PU Board 2019

Chemistry pu 2nd year Key answers 2019- Karnataka PU Board 2019
Download key answers 2019
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II PU CHEMISTRY ANSWER KEY

1.      Shrinks.

2.      Remains same

3.                    

4.      Zero

5.      Chemisorption.

6.      It selectively prevents ZnS from coming to the froth but allowesPbS to come with the froth

7.      Neon

dry ether

8.    R  X + 2 Na  +  X   R                  → R  −  R + 2Na    X

Alkane

9.      LiAlH₄

10.   B₁₂

PART –B

11. d = ZM

N₀a³

d= 2 × 7

(  6.022× 10²³) ( 352×10 ^-10) ³

=  0.53g/ml

11.   When same quantity of electricity passes through solutions of different electrolytes, the amounts of substances liberated at the electrodes are directly proportional to their chemical equivalent masses.

12.   A reaction which appears to be of higher order but made to follow first order kinetics by taking the other reactants except one in large excess.

Eg: Acid hydrolysis of ethyl acetate: CH₃COOC₂H₅ + H₂O →CH₃COOH + C₂H₅OH

r    [CH₃COOC₂H₅] [H₂O]⁰   ; order = 1

14.  i) As in actinoids the outer electrons are less firmly held, they are easily available for bonding.

ii) Due to Lanthanoid contraction

15) 

16.    2 C6H5CHO + NaO HC    OONa + C6H5CH2OH

“Cannizzarro reaction”

17.  i)In anionic deterge nts large part of the molecules is anion and it is the anionic part of the molecule which is involved in their cleansing action.

ii)  Artificial sweeten er.

18.  i)Norethindrone orethynylestradiolor novestrol ii)Morphine or heroi n or codeine

PART –C

19. a) i)2Al₂O₃ + 3C   4Al + 3CO₂

ii)    The molten cryolite decreases the melting point and also increases the electrical conductivity.

b)  Nickel

20.  Flow chart

N_2(g) + 3H_2(g)⇄2NH_3(g)                        H = -46.1 kJmol^-1

The optimum condition of a pressure of 200 bar and 750 K are use d along with the catalyst such a finely divided iron with small amount of molybdenum, or potassium oxide or aluminium oxide as promoter

21.  i) In H₂O electronegat ive element like oxygen is present that involv es I hydrogen bonding.

ii)   Conc. H₂SO₄ has hi gh affinity for water.

22.  i) NH₃ + 3Cl₂     NCl₃ + 3HCl

ii)    Na₂SO₃ + 2HCl 2NaCl +H₂O  +SO₂

ii)  Br₂  +3F₂    2 BrF₃

23.
	4FeCr2O4  + 16NaOH	+	7O2   →	8NaCrO4  + 2Fe2O3  + 8H2O
	2Na2CrO4 + conc.H2SO4	→  Na2Cr2O7		+ Na2SO4  + H2O
	Na2Cr2O7   + 2KCl	→	K2Cr2O7	+ 2NaCl

24.i)These are the compounds formed when the smaller atoms of H, C, N and B occupy the interstitial places in the metallic crystals of d-block.

ii)  a. Transition metals exhibit variable oxidation states due to the presence of unpaired d-electrons.

b. Finely powdered transition metals provide a large surface area.

25.  a) potassium trioxalatochromate(III)

b)

 

26.The electronic configuration of nickel (Z = 28) in the ground state is [Ar] 3d84s2. In the +2 oxidation state, the configuration of nickel is [Ar] 3d84s0.

When cyanide ligands approach the Ni2+ ion the unpaired 3d electrons get paired up against Hund’s rule leaving one of the d orbitals vacant.

Now dsp2 hybridisation takes place giving four vacant hybrid orbitals directed to the four corners of a square. The electron pairs donated by cyanide ligands occupy the dsp2 hybrid orbitals of Ni2+ ion

 Due to the absence of unpaired electrons, the inner orbital complex will be diamagnetic.

The complex has a square planar shape.

Frenkel defect is the displacement of few smaller ions (generally cation is smaller than anions) from their normal position to the interstitial sites.

Density remains same.

b)  Frenkel defect is the displacement of few smaller ions (generally cation is smaller than anions) from their normal position to the interstitial sites.

Density remains same.

   

a)   The process of reversing the direction of osmosis by applying the pressure higher than the osmotic pressure to the solution of higher concentration is called reverse osmosis.

    

      

      

         31)A) Zeolites are microporousaluminosilicates with three dimensional network of silicates           in which some silicon atoms are replaced by aluminium atoms giving Al-O-Si framework.             ZSM -5

B)   The process of conversion of freshly prepared precipitate into a colloidal solution by adding an electrolyte containing the common ion is calledpeptisation. Example: Ferric hydroxide sol

c)   ^x  = kp^{1/ n} , where x is the mass of the gas adsorbed on mass m of the adsorbent

m

at pressure P, k and n are constants which depend on the nature of the adsorbent and the gas at a particular temperature.

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