Q25 of 26 Page 1

(a) Account for the following :

(i) Bi(V) is a stronger oxidizing agent than Sb(V).


(ii) H – O – I is a weaker acid than H – O – Cl.


(iii) Bond angle decreases from H2O to H2S.


(b) Draw the structures of the following:


(i) SF4 (ii) XeF2


OR


(i) Why does PCl5 fume in moisture?


(ii) Write the name of the allotrope of sulphur which is stable at room temperature.


(iii) Chlorine water on standing loses its yellow colour. Why?


(iv) Write the disproportionation reaction of H3PO3.


(v) Complete the following equation:


F2 + H2O →


(a) (i) Since, Bi is not stable in +5 oxidation state due to inert pair effect so Bi(V) is a strong oxidizing agent i.e. it will oxidize others and itself will get reduced to a lower stable oxidation state like +3.


(ii) H – O – I is a weaker acid than H – O – Cl because Cl is more electronegative than F due to which the polarity of OH bond increases i.e. more the electronegativity of the halogen atom, more will be the tendency to pull electron towards itself and weaker will be the OH bond and hence H+ can easily be removed thereby increasing the acidity.


(iii) Bond angle decreases from H2O to H2S because O is more electronegative than S due to which the electrons of 2 O-H bonds are more towards O and the bond pair – bond pair repulsion increases which further increases the bond angle.


(b) (i) SF4



Geometry- trigonal bipyramidal, shape- see saw


(ii) XeF2



Geometry- trigonal bipyramidal, shape- linear


OR


(i) PCl5 fumes in moisture due to formation of HCl.


PCl5 + 4H2O → H3PO4 + 5HCl


(ii) The name of the allotrope of sulphur which is stable at room temperature is Rhombic sulphur ().


(iii) Chlorine water on standing loses its yellow colour due to formation of HCl and HOCl.


Cl2 + H2O → HCl + HOCl


(iv) On heating, H3PO3 disproportionates into phosphoric acid and phoshine.


4H3PO3 → 3 H3PO4 + PH3


(v) 2F2 + 2H2O → O2 + 4H+ + 4F-


More from this chapter

All 26 →
22

How do you convert the following:

(i) Aniline to phenol


(ii) Prop-1-ene to Propan-1-ol


(iii) Anisole to 2-methoxytoluene


OR


What happens when


(i) ethanol is treated with Cu at 573 K,


(ii) phenol is treated with CH3COCl / anhydrous AlCl3,


(iii) ethyl chloride is treated with NaOCH3 ?


Write chemical equations in support of your answer.


 23

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 junk food 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. Roy conducted the 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:

(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 tranquilizers? Give an example.


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


 24

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


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


(b) Calculate the average rate of reaction between the time interval 20 to 40 seconds.


OR


(a) Define the following terms:


(i) Collision frequency


(ii) Rate constant (k)


(b) The rate constant of a first order reaction increases from 410-2 to 2410-2 when the temperature changes from 300 K to 350 K. Calculate the energy of activation (Ea). (log 2 = 0.301, log 3 = 0.4771, log 4 = 0.6021, log 6 = 0.7782)


 26

Write the structures of A, B, C, D and E in the following reactions:


OR


(a) Write the structures of the main products when benzene diazonium chloride reacts with the following reagents:


(i) KI


(ii) CH3CH2OH


(iii) Cu/HCl


(b) Arrange the following in the increasing order of their basic character in an aqueous solution:


CH3NH2, (CH3)2NH, (CH3)3N


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


C6H5NH2 and CH3-NH2