41.

Write the name of vitamin whose deficiency causes bone deformities in children.

Give reasons:

n-Butyl bromide has higher boiling point than t-butyl bromide.

Give reasons:

Racemic mixture is optically inactive.

Give reasons:

The presence of nitro group (–NO₂) at o/p positions increases the reactivity of haloarenes towards nucleophilic substitution reactions.

Mr. Roy, the principal of one reputed school organized a seminar in which he invited parents and principals to discuss the serious issue of diabetes and depression in students. They all resolved this issue by strictly banning the junk food in schools and to introduce healthy snacks and drinks like soup, lassi, milk etc. in school canteens. They also decided to make compulsory half an hour physical activities for the students in the morning assembly daily. After six months, Mr. Roy 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:

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

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

(iii) What are tranquillizers? Give an example.

(iv) Why is use of aspartame limited to cold foods and drinks?

 Write the structures of main products when aniline reacts with the following reagents:

 (i) Br₂ water

 (ii) HCl

 (iii) (CH₃CO)₂O/pyridine

Arrange the following in the increasing order of their boiling point: C₂H₅NH₂, C₂H₅OH, (CH₃)₃N

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

(CH₃)₂NH and (CH₃)₃N.

For the hydrolysis of methyl acetate in aqueous solution, the following results were obtained:

 (i) Show that it follows pseudo-first order reaction, as the concentration of water remains constant.

(ii) Calculate the average rate of reaction between the time intervals 30 to 60 seconds.

 (Given log 2 = 0.3010, log 4 = 0.6021)

(i) Which allotrope of phosphorus is more reactive and why?

(ii) How the supersonic jet aeroplanes are responsible for the depletion of ozone layers?

(iii) F₂ has lower bond dissociation enthalpy than Cl₂. Why?

(iv)  Which noble gas is used in filling balloons for meteorological observations?

 (v) Complete the equation: XeF2 + PF5 →