Question
Explain Cross aldol condensation with suitable example. ### Write a short note: Cross aldol condensation.
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Answer
→ Cross aldol condensation : "When aldol condensation is carried out between two diferite and/or ketones, it is called cross aldol condensation." If both of them contain $\alpha$-hydrogen atoms, it gives a mixture of four products. This is illustrated below by aldol reaction of a mixture of ethanal and propanal.
→ Ketones can also be used as one component in the cross aldol reactions.
→ Ketones can also be used as one component in the cross aldol reactions.
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The actinoids include the fourteen elements from Th to Lr. The actinoids are radioactive elements and the earlier members have relatively long half-lives, the latter ones have half-life values ranging from a day to 3 minutes for lawrencium. The latter members could be prepared only in nanogram quantities. Actinoids show a greater range of oxidation states. The elements, in the first half of the series frequently exhibit higher oxidation states. The actinoids resemble the lanthanoids in having more compounds in +3 state than in the +4 state. All the actinoids are believed to have the electronic configuration of 7s2 and variable occupancy of the 5f and 6d subshells. The magnetic properties of the actinoids are more complex than those of the lanthanoids. The variation in the magnetic susceptibility of the actinoids with the number of unpaired 5f electrons is roughly parallel to the corresponding results for the lanthanoid.
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ii. Actinoids show irregularities in their electronic configuration. Justify?
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The actinoids include the fourteen elements from Th to Lr. The actinoids are radioactive elements and the earlier members have relatively long half-lives, the latter ones have half-life values ranging from a day to 3 minutes for lawrencium. The latter members could be prepared only in nanogram quantities. Actinoids show a greater range of oxidation states. The elements, in the first half of the series frequently exhibit higher oxidation states. The actinoids resemble the lanthanoids in having more compounds in +3 state than in the +4 state. All the actinoids are believed to have the electronic configuration of 7s2 and variable occupancy of the 5f and 6d subshells. The magnetic properties of the actinoids are more complex than those of the lanthanoids. The variation in the magnetic susceptibility of the actinoids with the number of unpaired 5f electrons is roughly parallel to the corresponding results for the lanthanoid.
i. Actinoid contraction is greater from element to element than lanthanoid contraction. Why?
ii. Actinoids show irregularities in their electronic configuration. Justify?
iii. The actinoid metals are all silvery in appearance but display a variety of structures than lanthanoid give reason.
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iii. The magnetic properties of the actinoids are more complex than those of the lanthanoids. Why?
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