In: Chemistry
1) Which of the following changes will temporarily shift the position of the equilibrium in the reverse direction for the reaction: N2(g) + 3H2(g) <--> 2NH3(g)
a) increase the concentration of NH3
b) decrease concentration of NH3
c) decrease concentraion of H2
d) increase concentration of N2
e)more than one of the choices would temporarily shift equilibrium in reverse direction
2)The solution resulting from the addition of a nonvolatile solute to a solvent will always have:
a) a higher freezing point than the pure solvent
b) a lower boiling point than pure solvent
c) both a lower freezing point and a higher boiling point than pure solvent
d) both a lower freezing point and lower boiling point than pure solvent
e) more than opne choice is correct
3) Which of the following solutions be hypotonic relative to red blood cells?
a) isotonic saline solution
b) 0.20 M saline solution
c) 0.25 osmol saline solution
d) 0.99% (m/v) saline solution
4) Which of the following statements about solutions is incorrect?
a) a solution is a homogeneous mixture
b) it is possible to have solutions in which both solute and solvent are solids
c) solutions do not seperate into solute and solvent, even if left undisturbed for long periods
d) the properties of a solution do not changes as the ratio of solute to solvent is changed.
5)An osmotic semi-permeable membraine is a membrane through which:
a) both solvent and solute molecules can pass
b) solvent but not solute molecules can pass
c) solute but not solvent molecules can pass
Ans. (1) From Le Chatelier principle, in reactant there are total four species and in product only two species, so reaction will proceed in forward direction that is more NH3 will form in this case but if you increase the concentration of NH3 after equibrium then reaction will go in the backward direction. From this conclusion the correct option will be (a) increase the concentration of NH3.
Ans. (2) The solution resulting from the addition of a nonvolatile solute to a solvent will always have two results:-
The boiling point of the solvent in a solution is higher than that of the pure solvent and the freezing point (melting point) of the solvent in a solution is lower than that of the pure solvent. So the correct option will be (c) both a lower freezing point and a higher boiling point than pure solvent.
Ans. (3) Hypotonic solution relative to red blood cells is 0.99% (m/v) saline solution. So the correct option will be (d) 0.99% (m/v) saline solution.
Ans. (4) The incorrect statements about solutions is the properties of a solution do not change as the ratio of solute to solvent is changed. Because if you change the ratio of solute to solvent, properties of solution will also change. So the correct option will be (d) the properties of a solution do not changes as the ratio of solute to solvent is changed.
Ans. (5) An osmotic semi-permeable membraine is a membrane through which solute molecules but not solvent molecules can pass. So the correct option will be (c) solute but not solvent molecules can pass.