How many ions per molecule are produced in the solution, when Mohr salt is dissolved in excess of water?
4
5
6
10
Which of the following aqueous solution has the highest freezing point?
0.1M surcose
0.01 M NaCl
0.1 M NaCl
0.01 M Na2SO4
Half-life period of a first order reaction is 10 min. Starting with initial concentration 12 M, the rate after 20 min is
0.0693 M min-1
0.693 × 3M min-1
0.0693 × 3M min-1
0.0493 × 4M min-1
The aqueous solution of following salt will have the lowest pH
NaClO3
NaClO
NaClO2
NaClO4
D.
NaClO4
The salts of strong acids give acidic solution (having pH less than 7).In the given salts, acid strength of oxoacids of chlorine increases with increase in oxidation number of chlorine.
Oxidation number (x) of Cl in HClO4 ( perchloric acid)
1+ x-8 = 0
x= +7
Oxidation number of Cl in HClO3 ( chloric acid)
1+ x-6 = 0
x= +5
Oxidation number of Cl in HClO2 (chlorous acid)
1+ x-4 = 0
x= +3
Oxidation number of Cl in HClO (hypochlorous acid)
1+x-2 =0
x= +1
So, acidic strength decreases in the order
( Most acidic)HClO4 > HClO3 > HClO2 > HClO(less acidic)
So, HClO4 is the strongest acid and salt of this aod NaClO4, will have the lowest pH
For one of the element various successive ionisation enthalpies (in kJ mol-1) are given below.
1st | 2nd | 3rd | 4th | 5th | |
IE | 5775 | 1810 | 2750 | 11,580 | 14820 |
The element is
Si
P
Al
Mg
How many Coulombs of electricity are required for the oxidation of one mole of water to dioxygen?
9.65 × 104 C
1.93 × 104 C
1.93 × 105 C
19.3 × 105 C
Which of the following colloids cannot be easily coagulated?
Lyophobic colloids
Multimolecular colloids
Macromolecular colloids
Irreversible colloids
The complex ion having minimum magnitude of Δ° (CFSE) is
[Cr(CN)6]3-
[Co(CN3)6]3+
[Co(Cl)6]3+
[Cr(H2O)6]3+
Cryolite is
Na3AlF6 and is used in the electrolysis of alumina for decreasing electrical conductivity
Na3AlF6 and is used in the electrolysis of alumina for lowering the melting point of alumina only ·
Na3AlF6 and is used in the electrolysis of alumina for lowering the melting point and increasing the conductivity of alumina
Na3AlF6 and is used in the electrolytic refining of alumina