Q26 of 26 Page 1

(a) Account for the following:

(i) Interhalogen compounds are more reactive than pure halogens.


(ii) N2 is less reactive at room temperature.


(iii) Reducing character increases from NH3 to BiH3.


(b) Draw the structures of following compounds:


(i) H4P2O7 (Pyrophosphoric Acid)


(ii) XeF4


OR


(a) Which poisonous gas is evolved when white phosphorus is heated with conc. NaOH solution?Write the chemical equation involved.


(b)which noble gas ha sthe lowest boiling point?


(c) fluorine is a stronger oxidizing agnet than chlorine. Why?


(d) what happens when H3PO4 is heated?


(e) complete the equation:


PbS + O3 →


(a) (i)

Interhalogen are more reactive than pure halogen because interhalogens are hetrocompunds and there bond is weaker than X-X bond. So they can easily undergo hydrolysis.


(ii) N2 has triple bond between two N atoms. And as triple bond has a shorted bond length and is highly strong, its bond disassociation enthalpy is very high. So it is less reactive at room temperature.


(iii) the reducing character increases from NH3 to BiH3, as while moving own the group the size increases from N to Bi, so ability to make stable stable covalent H bonds also decreases due to increasing difference in size. With decreasing stability of H bonds reducing character increases.


(b) (i)


640px-Pyrophosphoric-acid-2D.png


(ii)


OR


(a) Phosphine gas is evolved when phosphorus is heated with conc NaOH.reaction involved is :


P4 + 3NaOH + 3H2O → PH3 + 3NaH2PO2


(b)The boiling point increase with increase in temperature. So helium has the lowest boiling point amongst noble gases.


(c) Fluorine due to its small size and higher electronegativity accepts electron much faster than chlorine, and hence acts as a better oxidisizing agent than chlorine.


(d) on heating, H3PO4 condenses two moles of water and forms polyphosphoric acid.


(e) PbS + O3 →PbSO4 + O2


More from this chapter

All 26 →
22

(i) Which one of the following is a polysaccharide: starch, maltose, fructose, glucose?

(ii) What is the difference between native protein and denatured protein.


(iii) Write the name of vitamin responsible for the coagulation of blood.


 23

Seeing the growing cases of diabetes and depression among young children, Mr. Lugani, the principal of one reputed school organized a seminar in which he invited parents and principals. 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. Lugani 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. Lugani?


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


(iii) What are antidepressant drugs? Give an example.


(iv) Name the sweetening agent used in the preparation of sweets for a diabetic patient.


 24

(a) Illustrate the following reactions giving suitable example in each case:

(i) Hoffman Bromide Degradation reaction.


(ii)Diazotization


(iii) Gabriel Phthaliamide Synthesis


(b) Distinguish between the following pair of compounds:


(i)Aniline and N-methylaniline


(ii) (CH3)2NH and (CH3)3N


OR


(a) write the structures of main products when benzene diazonium chloride (C6H5N2+Cl-) reacts with the following reagents


(i) CuCN/KCN


(ii) H2O


(iii) CH3CH2OH


(b) Arrange the following:


(i) C2H5NH2, C2H5OH, (CH3)3N – in the increasing order of their boiling point.


(ii) Aniline, p-nitroaniline, p-methylaniline-in the increasing order of their basic strength.


 25

(a) What is the rate of reaction? Write two factors that affect the rate of reaction?

(b) The rate of first order reaction increases from 4 × 10-2 to 8 × 10-2 when the temperature changes from 27° C to 37° C. Calculate the activation energy (Ea)


(Given: log2=0.301, log3 =0.4771, log4=0.6021)


OR


(a) for a reaction A + B → P, the rate is given by,


Rate = K [A][B]2


(i) How is the rate of reaction affected if the concentration of B is doubled?


(ii) What is the overall order of reaction if A is present in large excess?


(b) a first order reaction takes 23.1 minutes for 50% completion. Calculate the time required for 75% completion of this reaction. (log2=0.301, log3 =0.4771, log4=0.6021)