Q3 of 10 Page 69

The experiments conducted by two students are given below.

Experiment - 1


2 mL of sodium thiosulphate solution is taken in a test tube, heated and to it, 2 mL of HCl solution is added.


Experiment - 2


2 mL of sodium thiosulphate solution is taken in a test tube and to it, 2 mL of HCl solution is added.


a) In which experiment is the precipitate formed first? Justify your answer.


b) Write the balanced equation for the reaction.

a) The precipitate will form first in experiment-1 because of increasing the temperature the energy as well as the speed of molecules increases. As a result of the number of molecules undergoing effective collisions increases. So the reactant molecules will react more easily. Hence the rate of reaction will increase.

b) Na2S2O3(aq) + 2HCl(aq) 2NaCl(aq) + H2O(l) + SO2(g) + S(s)


Note- In balanced equation, the number of atoms of an element will be same on both side of reaction.


More from this chapter

All 10 →
6

N2(g) + 3H2(g) ⇋ 2NH3(g) + heat

a) In this reaction what happens to the volume when the reactants change to the products?


b) What change in pressure is required for the maximum yield of the product?


c) What is the change in the concentration required for increasing the rate of the forward reaction?


d) What is the catalyst used in this reaction? What is its effect?

 1

Some apparatus and chemicals are given.

Zn, Mg, dilute HCl, CaCO3, test tube, water


a) Design an experiment to prove that the nature of reactants can influence the rate of reaction.


b) Write the equations for the chemical reactions.


c) Write the expression for the rate of the reaction.

 2

The graph for the reaction N2 (g) + 3H2 (g) ⇋ 2NH3 (g) + heat is given below.


a. Identify and write the reactions C and D.


b. What happens to the position of point A in the graph when a catalyst is used? Redraw the graph accordingly.

 4

Some materials available in the laboratory are given below. Magnesium ribbon, marble powder, marble pieces, dilute HCl, concentrated HCl.

a) Which are the materials required for the preparation of more CO2 in less time?


b) Write the balanced chemical equation for the reaction.