Practice free Co-ordination Compounds (Chemistry) NEET multiple-choice questions online with instant answers and detailed explanations. No login required.
Which of the following compounds has a primary valence of 2 for the metal ion, according to Werner's initial examples?
The NCERT states, 'Binary compounds such as $CrCl_3$, $CoCl_2$ or $PdCl_2$ have primary valence of 3, 2 and 2 respectively.' For $PdCl_2$, the primary valence is given as 2.
The spatial arrangements of ions/groups bound by secondary linkages to the metal in coordination compounds are referred to as:
The NCERT states, 'The ions/groups bound by the secondary linkages to the metal have characteristic spatial arrangements corresponding to different coordination numbers. In modern formulations, such spatial arrangements are called coordination polyhedra.'
What kind of bonds are modern chemists' understanding of Werner's 'ionisable (ionic) linkages' and 'non-ionisable (covalent) linkages' respectively?
The NCERT states, 'His theory postulated the use of two types of linkages (primary and secondary) by a metal atom/ion in a coordination compound. In the modern language of chemistry these linkages are recognised as the ionisable (ionic) and non-ionisable (covalent) bonds, respectively.'
Alfred Werner's theory was crucial in predicting the geometrical shapes of many coordination entities. Which of the following shapes are explicitly mentioned as more common in transition metal coordination compounds?
The NCERT text notes, 'He further postulated that octahedral, tetrahedral and square planar geometrical shapes are more common in coordination compounds of transition metals.'
Which of the following was NOT a question that Werner's theory could not fully answer?
The NCERT lists the limitations: '(i) Why only certain elements possess the remarkable property of forming coordination compounds? (ii) Why the bonds in coordination compounds have directional properties? (iii) Why coordination compounds have characteristic magnetic and optical properties?' However, the text also mentions 'Using the property of isomerism, Werner predicted the geometrical shapes of a large number of coordination entities', implying his theory could explain isomerism to some extent.
What characteristic of the counter ions outside the square bracket in coordination compounds is implied by Werner's theory?
The NCERT states, 'The species within the square bracket are coordination entities or complexes and the ions outside the square bracket are called counter ions.' It also says, 'The primary valences are normally ionisable and are satisfied by negative ions.' The examples with AgCl precipitation clearly demonstrate that ions outside the square bracket (counter ions) are ionisable.
Based on Werner's experiments, if 1 mol of a cobalt(III) chloride and ammonia compound with empirical formula $CoCl_3\cdot 4NH_3$ gives 1 mol of AgCl upon adding excess silver nitrate, what would be the modern formulation of this compound?
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 $[Co(NH_3)_4Cl_2]Cl$.
Which of the following terms is NOT directly associated with Werner's theory of coordination compounds based on the provided context?
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.
Werner's experiments on cobalt(III) chloride compounds and ammonia showed that some compounds with identical empirical formulas, like $CoCl_3\cdot 4NH_3$, could have distinct properties (e.g., green vs. violet). What phenomenon did Werner use to explain this observation?
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.
What was the primary experimental evidence that led Werner to propose two types of valencies?
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.
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