question_answer11) (i) Extraction of Au by leaching with NaCN involves both oxidation and reduction. Justify by giving equations for the reactions involved. (ii) Why is froth floatation method selected for the concentration of sulphide ores? View Answer play_arrow
question_answer16) Out of ,andwhich is more easily hydrolysed by aqueous KOH? Give reason.  Or The treatment of alkyl chlorides with aqueous KOH leads to the formation of alcohols, but in presence of alcoholic KOH, alkenes are major products. Explain. View Answer play_arrow
question_answer19) Silver crystallises with face-centred cubic unit cell. Each side of this unit cell has a length of 409 pm. What is the radius of silver atom? Assume the atoms just touch each other on the diagonal across the face of the unit cell.  Or Aluminium crystallises in a cubic close packed structure. Radius of the atom in the metal is 125 pm. (i) What is the length of the side of the unit cell? (ii) How many unit cells are there in 1cm3 of aluminium? View Answer play_arrow
question_answer21) 0.6 mL of acetic acid () having density 1.06 g is dissolved in 1 litre of water. The depression in freezing point observed for this strength of acid was 0.0205?C. Calculate the van't Hoff factor and the dissociation constant of acid. View Answer play_arrow
question_answer23) There is growing interest in the use of chelate therapy in medicinal chemistry. An example is the treatment of problems caused by the presence of metals in toxic proportions in plant/animal systems. Detection of cations through coloured complex formation is done in qualitative analysis. Read the above passage and answer the following questions. (a) Name the chelating agents that can remove copper, iron and lead from water,  (b) Name the compound that inhibits the growth of tumours.  (c) Recent studies show that cis-platin can cause serious side effects; including severe kidney damage. What is the alternative medicine? View Answer play_arrow
question_answer24) (i) Using valence bond theory, predict the geometry and magnetic character of . (ii) Among octahedral and tetrahedral crystal fields, in which case the magnitude of crystal field splitting is larger? View Answer play_arrow
question_answer27) Give reasons for the following observations. (a) Peptizing agent is added to convert precipitate into colloidal solution. (b) Cottrell's smoke precipitator is fitted at the mouth of chimney used in factories. (c) Colloidal gold is used for intramuscular injection. [3 x 1]View Answer play_arrow
question_answer28) Explain the following. (i) MnO is basic while is acidic in nature. (ii) Chromium is a typical hard metal but mercury is a liquid. (iii) The transition metals form a large number of complex compounds. (iv) The highest oxidation state of a metal is exhibited in its oxide or fluoride only. (v) E? value for the couple is much more positive than that foror[5x1] Or (i) Complete the following reactions. (a) (b) (ii)Which of the following has the maximum number of unpaired electrons? (iii) Give two consequences of lanthanide contraction. (iv) Based on the data, arrange and in the increasing order of stability of + 2 oxidation state. (v) Calculate spin only magnetic moment of View Answer play_arrow
|Experiment||time||Total pressure (atm)|
|I II||0 100||0.5 0.6|
question_answer30) (a) An organic compound (A) with the molecular formula forms 2, 4-DNP derivative reduces Tollen's reagent and undergoes Cannizzaro reaction. On vigorous oxidation it gives 1,2-benzene dicarboxylic acid. Identify the compound (A). (b) Give simple chemical tests to distinguish between the following pairs of compounds. (i) Phenol and benzoic acid (ii) Benzaldehyde and acetophenone. [3 + 3] Or (a) Predict the products of the following reactions.
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