1
AIPMT 2003
MCQ (Single Correct Answer)
+4
-1
The radioistope, tritium ($${}_1^3$$H) has a half-life of 12.3 years. If the initial amount of tritium is 32 mg, how many milligrams of it would remain after 49.2 years?
A
1 mg
B
2 mg
C
4 mg
D
8 mg
2
AIPMT 2003
MCQ (Single Correct Answer)
+4
-1
Which one of the following characteristics of the transition metals is associated with their catalytic activity?
A
High enthalpy of atomization
B
Paramagnetic behaviour
C
Colour of hydrated ions
D
Variable oxidation states
3
AIPMT 2003
MCQ (Single Correct Answer)
+4
-1
The correct order of ionic radii of Y3+, La3+, Eu3+ and Lu3+ is
(Atomic nos. Y = 39, La = 57, Eu = 63, Lu = 71)
A
Y3+ < La3+ < Eu3+ < Lu3+
B
Y3+ < Lu3+ < Eu3+ < La3+
C
Lu3+ < Eu3+ < La3+ < Y3+
D
La3+ < Eu3+ < Lu3+ < Y3+
4
AIPMT 2003
MCQ (Single Correct Answer)
+4
-1
The densities of graphite and diamond at 298 K are 2.25 and 3.31 g cm$$-$$3, respectively. If the standard free energy difference $$\left( {\Delta {G^o}} \right)$$ is equal to 1895 J mol$$-$$1, the pressure at which graphite will be transformed into diamond at 298 K is
A
11.14 $$ \times $$ 108 Pa
B
11.14 $$ \times $$ 107 Pa
C
11.14 $$ \times $$ 106 Pa
D
11.14 $$ \times $$ 105 Pa