Freezing point of water is 0°C. At what temperature will one molal solution of NaCl freeze if NaCl is taken to be completely dissociated (molal depression constant of water = 1.86)?
-3.72°C
-1.86°C
0°C
3.72°C
The half-life of a radioactive element is 30min, one sixteenth of original quantity of element will remain unchanged after
1 h
16 h
4 h
2 h
If the amount of radioactive substance is increased three times, the number of atoms disintegrated per unit time would
be double
be triple
remain one third
not change
Half-life of a radioactive element is 100yr. The time in which it disintegrates to 50% of its mass, will be
50 yr
200 yr
100 yr
25 yr
120 gm urea is present in 5 L solution, the active mass of urea is
0.2
0.06
0.4
0.08
C.
0.4
Weight of urea = 120 gm
Volume of solution = 5L
Molecular weight of urea = 60 u
Active mass =
Active mass =
Active mass = 0.4 mol/ L
The term (dc/ dt)in a rate equation refers to the
concentration of the reactant
decreases in concentration of the reactant with time
increase in concentration of the reactant with time
velocity constant of the reaction
If the rate expression for a chemical reaction is given by rate = k[A]m[B]n
the order of the reaction is m
the order of the reaction is n
the order of the reaction is m + n
the order of the reaction is m- n