Q30 of 53 Page 1

(a) Write the products formed when CH3CHO reacts with the following reagents:

(i) HCN


(ii) H2N-OH


(iii) CH3CHOin the presence of dilute NaOH


(b) Give simple chemical tests to distinguish between the following pairs of compounds:


(i) Benzoic acid and Phenol


(ii) Propanal and Propanone


OR


(a) Account for the following:


(i) Cl-CH2COOH is stronger acid than CH3COOH


(ii) Carboxylic acids do not give reactions of carbonyl group.


(b) Write the chemical equations to illustrate the following name reactions:


(i) Rosenmund reduction


(ii) Cannizzaro’s reaction


(c) Out ofCH3CH2-CO-CH2CH3 and CH3CH2-CH2-CO-CH3, which gives iodoform test?


(a) (i) CH3CHO + HCN → CH3-CH(CN)-OH


(ii) CH3CHO + H2N-OH → CH3CH=N-OH


(iii)


(b) (i) Add neutral FeCl3 in both the solutions, phenol forms violet colour but benzoic acid does not.


(ii) Tollen’s reagent test: Add ammonical silver nitrate (Tollen’s reagent) in both the solutions. Propanal gives silver mirror whereas propanone does not.


OR


(a) (i) Chlorine acts as electron withdrawing group, so it helps in dispersing the negative charge on carboxylate ion after releasing of H+ ions and thus making it stable. So, Cl-CH2COOH is stronger acid than CH3COOH


(b) (i) Rosenmund reduction:


Or



(ii) Cannizzaro’s Reaction:


(c) CH3CH2-CH2-CO-CH3 shows iodoform test because it has a terminal methyl ketone group.


More from this chapter

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28

(a) Define the following terms:
(i) Molarity
(ii) Molal elevation constant (Kb)

(b) A solution containing 15 g urea (molar mass = 60 g/mol) per litre of solution in water has the same osmotic pressure (isotonic) as a solution of glucose (molar mass = 180 g/mol) in water. Calculate the mass of glucose present in one litre of its solution.


OR


(a) What type of deviation is shown by a mixture of ethanol and acetone? Give reason.


(b) A solution of glucose (molar mass = 180 g/mol) in water is labelled as 10% (by mass). What would be the molality and molarity of the solution?


(Density of solution = 1.2 g/mL)


 29

(a) Complete the following equations:

(i) Cr2O72- + 2OH- →


(ii) MnO4- + 4H+ +3e- →


(b) Account for the following:


(i) Zn is not considered as a transition element.


(ii) Transition metals form a large number of complexes.


(iii) The E0 value for the Mn3+/ Mn2+ couple is much more positive than that for the Cr3+/ Cr2+ couple.


Or


(i) With reference to structural variability and chemical reactivity, write the differences between lanthanoids and actinoids.


(ii) Name a member of the lanthanoid series which is well known to exhibit +4 oxidation state.


(iii) Complete the following equation:


MnO4- + 8H+ + 5e-→


(iv) Out of Mn3+ and Cr3+, which is more paramagnetic and why?


(Atomic no.: Mn= 25, Cr= 24)


 1

Why is adsorption always exothermic ?

 2

Name the method that is used for refining of nickel.