11.

A process is taking place at constant temperature and pressure. Then

• ΔH = ΔE=0

• ΔH= TΔS

• ΔH= 0

• ΔS= 0

In a mixture of acetic acid and sodium acetate the ratio of concentrations of the salt to the acid is increased ten times. Then the pH of the solution

• increases by one

• decreases by one

• decreases ten fold

• increases ten fold

The enthalpy of combustion of methane at 25°C is 890 kJ. The heat liberated when 3.2 g of methane burnt in air is

• 445 kJ

• 278 kJ

• -890 kJ

• 178 kJ

Select the pK_a value of the strongest acid from the following

• 1.0

• 3.0

• 2.0

• 4.5

The compounds A and B are mixed in equimolar proportion to form the products, A +B $\rightleftharpoons$ C+ D. At equilibrium, one third of A and B are consumed. The equilibrium constant for the reaction is

• 0.5

• 4.0

• 2.5

• 0.25

Hydrogen diffuses six times faster than gas A. The molar  mass of gas A is

• 72

• 6

• 24

• 36

Dulong and Petit's law is valid only for

• metals

• non-metals

• gaseous elements

• solid elements

In acetylene molecule, the two carbon atoms are linked by

• one sigma-bond and two pi-bonds

• two sigma-bonds and one pi-bond

• three sigma-bonds

• three pi-bonds

Pick out the alkane which differs from the other members of the group

• 2,2-dimethyl propane

• pentane

• 2-methyl butane

• 2,2-dimethyl butane

In qualitative analysis, in order to detect second group basic radical, H₂S gas is passed in the presence of dilute HCl to

• increase the dissociation of H₂S

• decrease the dissociation of salt solution

• decrease the dissociation of H₂S

• increase the dissociation of salt solution