1
JEE Main 2021 (Online) 27th July Evening Shift
MCQ (Single Correct Answer)
+4
-1
The number of neutrons and electrons, respectively, present in the radioactive isotope of hydrogen is :
A
1 and 1
B
3 and 1
C
2 and 1
D
2 and 2
2
JEE Main 2021 (Online) 27th July Evening Shift
MCQ (Single Correct Answer)
+4
-1
To an aqueous solution containing ions such as Al3+, Zn2+, Ca2+, Fe3+, Ni2+, Ba2+ and Cu2+ was added conc. HCl, followed by H2S.

The total number of cations precipitated during this reaction is/are :
A
1
B
3
C
4
D
2
3
JEE Main 2021 (Online) 25th July Morning Shift
MCQ (Single Correct Answer)
+4
-1
At 298.2 K the relationship between enthalpy of bond dissociation (in kJ mol$$-$$1) for hydrogen (EH) and its isotope, deuterium (ED), is best described by :
A
$${E_H} = {1 \over 2}{E_D}$$
B
$${E_H} = {E_D}$$
C
$${E_H} \simeq {E_D} - 7.5$$
D
$${E_H} = 2{E_D}$$
4
JEE Main 2021 (Online) 22th July Evening Shift
MCQ (Single Correct Answer)
+4
-1
The water having more dissolved O2 is :
A
boiling water
B
water at 80$$^\circ$$C
C
polluted water
D
water at 4$$^\circ$$C
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