A bottle of cold drink contains 200 ml liquid in which CO2 is 0.1 molar .Suppose CO2 behaves like an ideal gas , the volume of the dissolved CO2 at STP is :
0.224 L
22.4 L
0.448 L
44.8 L
If a salt bridge is removed between the half cells , the voltage :
decreases to zero
increases
increases rapidly
do not change
Lanthanum the first element of lanthanide series has :
only unfilled 3d orbitals
unfilled 3d and 4d orbitals
unfilled 4d and 4forbitals
unfilled 4f and 5d orbitals
A radioactive substance decays th of it original value in 2h. The half-life of the substance is :
1 h
30 min
20 min
15 min
The chemical reaction 2O3 3O2 proceeds as :
(I) O3 O2 + O (fast)
(II) O + O3 2O2 (slow)
The rate expression should be :
r = k[O3]2
r = k[O3]2 [O2]-1
r = k[O3] [O2]
None of these
Which of the following has more unpaired d-electrons ?
Zn
Fe2+
Ni3+
Cu+
B.
Fe2+
Zn : 1s2 , 2s2 2p6 , 3s2 3p6 3d10 , 4s2 ;
no unpaired electron
Fe2+ : 1s2 , 2s2 2p6 , 3s2 3p6 3d6 ;
four unpaired electron
Ni3+ : 1s2 2s2 2p6 , 3s2 3p6 3d7 ;
three unpaired electrons
Cu+ : 1s2 , 2s2 2p6 , 3s2 3p6 3d10 ;
no unpaired electron
Hence , Fe2+ has maximum number of unpaired electrons .
0.5 molal solution of ethylene glycol in water is used as coolant in car .If the freezing point depression constant ofwater is l.86°C per mol , the mixture will freeze at :
0.93 °C
- 0.93 °C
1.86 °C
- 1.86 °C