The valence shell electronic configuration of Cr2+ ion is :
4s03d4
3p64s2
4s33d2
4s23d0
A.
4s03d4
The valence shell electronic configuration of Cr+ ion is :
= 1s2 , 2s2 2p6 , 3s2 3p6 3d4 , 4s0
The structure of IF5 can be best described as :
None of these
D.
None of these
Number of hybrid orbitals = number of bp + number of lp
= 5 + 1 = 6
Thus , hybridisation is sp3d2 but geometry , due to the presence of one lone pair , is square pyramidal , i.e. ,
A solution contains 25% H2O , 25% C2H5OH and 50% CH3COOH by mass .The mole fraction of H2O would be :
0.25
2.5
0.502
5.03
C.
0.502
Mole fraction of H2O =
Let the total mass of solution = 100 g
Mass of H2O = 25 g
Mass of C2H5OH = 25g
Mass of CH3COOH = 50 g
Moles of H2O = = 1.388
( Molar mass of H2O = 18)
Moles of C2H5OH = = 0.543
( Molar mass of C2H5OH = 46)
Moles of CH3COOH = = 0.833
( Molar mass of CH3COOH = 60)
Total no. of moles = 1.388 + 0.543 + 0.833 = 2.764
Mole fraction of H2O = = 0.502
If the solubility of PbCl2 at 25°C is 6.3 x 10-2 mol/L , its solubility product is :
1 x 10-6
1 x 10-3
1.1 x 10-6
1.1 x 10-5
B.
1 x 10-3
PbCl2 completely ionised in the solution as
PbCl2 Pb2+ + 2Cl-
i.e , 1 mole of PbCl2 in the solution gives 1 mole of Pb2+ ion and 2 moles of Cl- ions .
Now , as the solubility of PbCl2
= 6.3 x 10-2 mol/L
[Pb2+] = 6.3 x 10-2 mol/L
and [Cl-] = 2 X 6.3 X 10-2 mol/L
= 12.6 x 10-2 mol/L
Ksp for PbCl2 = [Pb2+][Cl-]2
= (6.3 x 10-2) x (12.6 x 10-2)2
= 1 x 10-3
A double bond connecting two atoms .There is a sharing of :
2 electrons
1 electron
4 electrons
All electrons
C.
4 electrons
A double bond connecting two atoms , thus there is a sharing of 4 electrons .We can explain it by taking example of C-C double bond .
The percentage of p-character in the orbitals forming P-P bond in P4 is :
25
33
50
75
D.
75
Each P atom in P4 is sp3 hybridised , hence the percentage ofs and p character is 25% and 75% .
From elementary molecular orbital theory we can deduce the electronic configuration of the singly positive nitrogen molecular ion as :
1s2 , 1s2 , 2s2 , 2s2 , 2p4 , 2p1
1s2 , 1s2 , 2s2 , 2s2 , 2p2 , 2p3
1s2 , 1s2 , 2s2 , 2s2 , 2p3 , 2p2
1s2 , 1s2 , 2s2 , 2s2 , 2p2 , 2p4
A.
1s2 , 1s2 , 2s2 , 2s2 , 2p4 , 2p1
N2+ = (7 + 7 - 1 = 13)
1s2 , 1s2 , 2s2 , 2s2 , 2px2 2py2 , 2pz1
Ionisation potential is lowest for :
alkali metals
inert gases
halogens
alkaline earth metals
A.
alkali metals
The atomic radii of alkali metals are the largest in their respective periods due to which the ionisation enthalpy of the alkali metals are the lowest as compared to the elements in other groups .
Which of the following has largest atomic radii ?
Al
Al+
Al2+
Al3+
A.
Al
Atomic radii varies inversely with nuclear charge , ie ,
Atomic radii
pH of a solution can be expressed as :
-loge [H+]
-log10 [H+]
loge [H+]
log10[H+]
B.
-log10 [H+]
pH is defined as the negative logarithm of the hydrogen ion concentration in solution .
pH = -log10 [H+]
Severity: Notice
Message: Undefined variable: flex_subject_id
Filename: features/flexipad.php
Line Number: 348
Backtrace:
File: /var/www/html/public_html/application/views/features/flexipad.php
Line: 348
Function: _error_handler
File: /var/www/html/public_html/application/views/previous_year_papers/paper.php
Line: 163
Function: view
File: /var/www/html/public_html/application/controllers/Study.php
Line: 2109
Function: view
File: /var/www/html/public_html/index.php
Line: 315
Function: require_once