NEET Practice Questions (MCQs) with Answers & Solutions

The NCERT states: '1 mol $CoCl_3\cdot 4NH_3$ (Green) gave 1 mol AgCl'. This means only one chloride ion is ionisable (outside the coordination sphere). The remaining two chloride ions and four ammonia molecules must be inside the coordination sphere. Thus, the formula is $[Co(NH_3)_4Cl_2]Cl$.

Werner's theory established the concepts of primary and secondary valences and the idea of characteristic spatial arrangements (coordination polyhedra). Crystal Field Theory (CFT) is mentioned as a later theory ('The Crystal Field Theory (CFT) to coordination compounds is based on the effect of different crystal fields...'), building upon earlier ideas but not part of Werner's original postulates.

The NCERT states: 'Note that the last two compounds in Table 5.1 have identical empirical formula, $CoCl_3\cdot 4NH_3$, but distinct properties. Such compounds are termed as isomers.' Werner's theory provided a framework to understand such isomeric forms.

The NCERT states, 'In a series of compounds of cobalt(III) chloride with ammonia, it was found that some of the chloride ions could be precipitated as AgCl on adding excess silver nitrate solution in cold but some remained in solution.' This observation was key to differentiating ionisable (primary) and non-ionisable (secondary) valences.

The context states: 'Thionyl chloride is preferred because in this reaction alkyl halide is formed along with gases SO2 and HCl. The two gaseous products are escapable, hence, the reaction gives pure alkyl halides.'

The context mentions: 'The reactions of primary and secondary alcohols with HCl require the presence of a catalyst, ZnCl2.'

The context states: 'With tertiary alcohols, the reaction is conducted by simply shaking the alcohol with concentrated HCl at room temperature.'

The context states: 'Alkyl iodides are often prepared by the reaction of alkyl chlorides/bromides with NaI in dry acetone. This reaction is known as Finkelstein reaction.'

The context explains: 'NaCl or NaBr thus formed is precipitated in dry acetone. It facilitates the forward reaction according to Le Chatelier’s Principle.'

The context lists: 'AgF, Hg2F2, CoF2 or SbF3' as metallic fluorides used in Swarts reaction. NaF is not mentioned.