How many atoms are contained in 0.2moles of nitrogen? [NA=6.02×1023]
1.20×1023
2.41×1023
3.62×1023
4.82×1023
Correct answer is A
1mole=6.02×1023atoms
0.2moles=6.02×1023×0.2 atoms
= 1.204×1023
≊
When chlorine is passed through a sample of water, the pH of the water sample would be
< 7
> 7
= 7
0
Correct answer is A
Cl_{2} + H_{2}O \to HCl + HOCl
The two compounds in the product end are acidic and hence, their mixture is acidic. Hence, the pH is < 7
One of the criteria for confirming the purity of benzene is to determine its
heat capacity
boiling point
mass
colour
Correct answer is B
Any pure substance will have a specific melting and boiling point. The presence of impurities alters the boiling point of benzene.
Which of the following CANNOT be an empirical formula?
CH
CH_{2}
P_{2}O_{5}
N_{2}O_{4}
Correct answer is D
The empirical formula is always in the ratio of the smallest positive integer, hence, N_{2}O_{4} has an empirical formula NO_{2}
Cu and HNO_{3} are not suitable for preparing hydrogen gas because of their
reactivity and oxidation respectively
conductivity and corrosiveness respectively
melting point and reduction respectively
electronegativity and solubility respectively
Correct answer is A
Copper is not active enough to replace hydrogen in an acid. Also, nitric acid is a strong oxidizing agent which quickly oxidises hygrogen to water.