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
Point defects are present in
ionic solids
molecular solids
amorphous solids
liquids
A.
ionic solids
When deviation exist from the regular arrangement around an atom or a group of atoms in a crystalline substance, the defect are known as point defects. These are present in ionic solids only.
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
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