CaO and NaCl have the same crystal structure and approximately the same ionic radii. If U is the lattice energy ofNaCI, the approximate lattice energy of CaO is
U/2
U
2U
4U
D.
4U
Lattic energy =where q1 and q2 are charges on ions and r is the distance between them. Since interionic distances in CaO and NaCl are similar, (larger cation has smaller anion and vice versa) therefore, r is almost the same. Therefore, lattice energy depends only on charge. Since the magnitude of charge on Na+ and Cl-ions is unity and that on Ca2+ and O2- ions is 2 each, therefore, the lattice energy of CaO is four times the lattice energy of NaCl, i.e..4U.
100 cm3 of a given sample of H2O2 gives 1000 cm3 of O2 at S.T.P. The given sample is
10% H2O2
90% H2O2
10 volume H2O2
100 volume H2O2
C.
10 volume H2O2
Hydrogen peroxide can easily break down, or decompose, into water and oxygen by breaking up into two very reactive parts- either 2OH or an H and HO2.
or 1ml of H2O2 will give 10 ml of O2 at STP.
Beryllium and aluminium exhibit many properties which are similar. But the two elements differ in
maximum covalency in compounds
exhibiting amphoteric nature in their oxides
forming covalent halides
forming polymeric hydrides
A.
maximum covalency in compounds
Be exhibits maximum covalency of four whereas Al shows maximum covalency of six.
Match List I with List II and select the correct answer using the codes given below the lists:
List I | List II |
A. | 1. |
B. | 2. T |
C. | 3. -S |
D. | 4. P |
5. V |
A-5, B-1, C-2, D-4
A-5, B-3, C-2, D-4
A-3, B-5, C-2, D-1
A-5, B-3, C-2, D-1
D.
A-5, B-3, C-2, D-1
From thermodynamics, dG = VdP-SdT
At constant T, dT = 0 so that
At constant P dP = 0 so that
Also
In the ground state of Cu2+ the number of shells occupied, subshells occupied, filled orbitals and unpaired electrons respectively are
4, 8, 15 0
3, 6, 15, 1
3, 6, 14, 0
4, 7, 14, 2
C.
3, 6, 14, 0
Cu+ = 1s2 2s2 2p6 3s2 3p6 3d6
So, Shells occupied =3, sub- shell occupied = 6, filled orbital = 14 and unpaired electron = 0
Equal weight of CO and CH4 are mixed together in an empty container at 300 K. The fraction of total pressure exerted by CH4 is.
B.
Let tje weight of CO = weight of CH4
Total moles =
fraction of pressure exerted by CH4 = 7/11
Which of the following is correct?
Ionic radius is proportional to atomic number.
Ionic radius is inversely proportional to atomic mass.
Ionic radius is inversely proportional to effective nuclear charge.
All are correct.
C.
Ionic radius is inversely proportional to effective nuclear charge.
What is the pH of0.01 M glycine solution? For glycine Ka1= 4.5x10-3 and Ka2=1.7x10-10 298 K.
3.0
10.0
7.06
8.2
C.
7.06
Glycine H3N+CH2COO- is more acidic than basic. Instead of Kb value, the second given Ka value is corresponding to the Kb value ( Ka Kb = 10-14). Hence, overall ionization constant,
K= Ka1 Ka2
= 4.5 10-3 1.7
pH =-log (0.87 10-7) = 7.06
Two flasks X and Y have capacity 1L and 2L respectively and each of them contains 1 mole of a gas. The temperatures of the flasks are so adjusted that average speed of molecules in X is twice as those in Y. The pressure in flask X would be
same as that in Y
half of that in Y
twice of that in Y
8 times ofthat in Y
D.
8 times ofthat in Y
=8
Which ofthe following sequence contains atomic number of only representative elements?
55,12,48,53
13,33,54,80
3,33,53,87
22,33,55,66.
C.
3,33,53,87
Sequence (c) contains only representative elements.
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