Q25 of 26 Page 1

I) Calculate emf and G for the following cell:


Given: and


II) a) Conductivity of 0.20 mol L-1 solution of KCl is . Calculate its molar conductivity and degree of dissociation Given = 73.5 and = 76.5 .


b) What type of battery is mercury cell? Why is it more advantageous than dry cell?


I)


Given: and


Now,


n = 2 (2 electrons are getting transferred)





Putting all the values,




(Concentrations of Solids is 1 M)





Also,






II) a) conductivity (K) =


Concentration (c) = 0.20 mol L-1


Molar conductivity =



= 124


= 73.5


= 76.5 .








b) Mercury cell is a type of primary battery. In primary batteries, the charging reaction occurs only once and after a period of time, the battery becomes dead. Mercury cell is more advantageous than dry cell has a very short life span due to the conversion of zinc to zinc chloride that makes the zinc casing porous. Due to porous casing, the substance inside the cell leaks out and corrodes the metal, reducing the lifetime of the cell.


More from this chapter

All 26 →
22

a) Write the product obtained when D-glucose reacts with

b) Amino acids show amphoteric behaviour. Why?


c) Why cannot vitamin C be stored in our body?


 23

Seeing the growing cases of diabetes and depression among young children, Mr. Lugani, the principal of one reputed school organised a seminar in which he invited parents and principals. They all resolved this issue by strictly banning junk foods in schools and introducing healthy snacks and drinks like soup, lassi, milk etc in school canteens. They also decided to make compulsory half an hour of daily physical activities for the students in the morning assembly. After six months, Mr. Lugani conducted a health survey in most of the schools and discovered a tremendous improvement in the health of the students.

After reading the above passage, answer the following questions:


a) What are the values (at least two) displayed byMr. Lugani?


b) As a student, how can you spread awareness about this issue?


c) What are antidepressant drugs? Give an example.


d) Name the sweetening agent used in the preparation of sweets for diabetic patient.


 24

I) a) A compound ‘A’ of molecular formula undergoes a series of reactions as shown below. Write the structures of A, B, C and D in the following reactions.


b) Distinguish between the following:


i) and


ii) Benzoic acid and methyl benzoate


c) Write the structure of 2-methylbutanal.


II) a) Write the structures of the main products when acetone ) reacts with the following reagents:


i) Zn- Hg/conc HCl


ii)


iii)


b) Arrange the following in the increasing order of their boiling points:


, ,


c) Give a simple chemical test to distinguish between the following pair of compounds:


and


26

I) a) Account for the following:

i) Zr and Hf have almost similar atomic radii


ii) Transition metals show variable oxidation states


iii) ion is unstable in an aqueous solution


b) Complete the following equations:



II) a)



From the given data of values, answer the following questions:


i) Why is value exceptionally positive?


ii) Why is value highly negative as compared to other elements?


iii) Which is stronger reducing agent ? Give reason.


b) Why do actinoids show a wide range of oxidation states? Write one similarity between the chemistry of lanthanoids and actinoids.