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.
150\(cm^{3}\)
75\(cm^{3}\)
30\(cm^{3}\)
25\(cm^{3}\)
Correct answer is A
Using the formula, \(\frac{C_{A}V_{A}}{C_{B}V_{B}} = \frac{N_{A}}{N_{B}}\), we have
\(\frac{0.1 \times V_{A}}{0.3 \times 25} = \frac{2}{1}\)
\(V_{A} = \frac{0.3 \times 25 \times 2}{0.1 \times 1}\)
\(V_{A} = 150cm^{3}\)
Which of the following statements best explains the difference between a gas and a vapour?
Unlike gases, vapours are liquids at room temperature
Unlike gases, vapour can easily be condensed into liquids
Unlike gases, vapour is readily converted into solids
Vapours are generally denser than gases
Correct answer is B
Vapour is the equilibrium state between the gases and liquid, and it can bounce back to its original form, liquid with constant temperature and pressure exerted on it.