An element X (molar mass = 60 g mol^-1) has a density of 6.23 g cm^-3. Identify the type of cubic unit cell, if the edge length of the unit cell is 4× 10^-8 cm.

(a) How would you account for the following:

(i) Highest fluoride of Mn is MnF₄ whereas the highest oxide is Mn₂O₇.

(ii) Transition metals and their compounds show catalytic properties.

(b) Complete the following equation:

3 MnO₄^2- + 4 →

Predict the products of the following reactions:

(i)

(ii)

(iii)

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

After reading the above passage, answer the following questions;

(i) What are the values (at least two) displayed by Mr. Chopra?

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

(iii) Why should antidepressant drugs not be taken without consulting a doctor?

(iv) Give two examples of artificial sweetners.

(a) Define the following terms:

(i) Activation energy

(ii) Rate constant

(b) A first order reaction takes 10 minutes for 25% decomposition. Calculate t_1/2 for the reaction.

(Given: log2 = 0.3010, log3 = 0.4771, log4 = 0.6021)

OR

(a) For a chemical reaction R → P, the variation in the concentration, ln[R] vs. time(s) plot is given as

(i) Predict the order of the reaction.

(ii) What is the slope of the curve?

(iii) Write the unit of rate constant for this reaction.

(b) Show that the time required for 99% completion is double of the time required for the completion of 90% reaction.