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Under unfavourable conditions many zoo- ...

Under unfavourable conditions many zoo- plankton species in lakes and ponds are known to enter a stage of suspended development called

A

aestivation

B

migration

C

hibernation

D

diapause

Text Solution

Verified by Experts

The correct Answer is:
D
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Hyperconjugation describes the orbital interactions between the p-systems and the adjacent s-bond of the substituent group(s) in organic compounds. Hyperconjugation is also called as Baker and Nathen effect. The necessary and sufficient condition for the hyperconjugation are : i) Compound should have at least on sp2 hybrid carbon of either alkene, carbocation or alkyl free radical. ii) A-carbon with respect to sp2 hybrid carbon should have at least one hydrogen. Hyperconjugation are of three types: (i) s(C-H), p-conjugation. (iii) s(C-H), positive charge conjugation iv) s(C-H), odd electron conjugation The hyperconjugation may be represented as Number of resonating structures due to hyperconjugation = (n + 1) where n is the number of a-hydrogen. Greater is the number of such forms, more is the stability of the species under considersation. Hyperconjugation is possible in which of the following species ?

Hyperconjugation describes the orbital interactions between the p-systems and the adjacent s-bond of the substituent group(s) in organic compounds. Hyperconjugation is also called as Baker and Nathen effect. The necessary and sufficient condition for the hyperconjugation are : i) Compound should have at least on sp2 hybrid carbon of either alkene, carbocation or alkyl free radical. ii) A-carbon with respect to sp2 hybrid carbon should have at least one hydrogen. Hyperconjugation are of three types: (i) s(C-H), p-conjugation. (iii) s(C-H), positive charge conjugation iv) s(C-H), odd electron conjugation The hyperconjugation may be represented as Number of resonating structures due to hyperconjugation = (n + 1) where n is the number of a-hydrogen. Greater is the number of such forms, more is the stability of the species under considersation. Which of the following carbocations will show highest number of Hyperconjugation forms?

Hyperconjugation describes the orbital interactions between the p-systems and the adjacent s-bond of the substituent group(s) in organic compounds. Hyperconjugation is also called as Baker and Nathen effect. The necessary and sufficient condition for the hyperconjugation are : i) Compound should have at least on sp2 hybrid carbon of either alkene, carbocation or alkyl free radical. ii) A-carbon with respect to sp2 hybrid carbon should have at least one hydrogen. Hyperconjugation are of three types: (i) s(C-H), p-conjugation. (iii) s(C-H), positive charge conjugation iv) s(C-H), odd electron conjugation The hyperconjugation may be represented as Number of resonating structures due to hyperconjugation = (n + 1) where n is the number of a-hydrogen. Greater is the number of such forms, more is the stability of the species under considersation. Stability of saturated alkyl carbocations can be explained by

Hyperconjugation describes the orbital interactions between the p-systems and the adjacent s-bond of the substituent group(s) in organic compounds. Hyperconjugation is also called as Baker and Nathen effect. The necessary and sufficient condition for the hyperconjugation are : i) Compound should have at least on sp2 hybrid carbon of either alkene, carbocation or alkyl free radical. ii) A-carbon with respect to sp2 hybrid carbon should have at least one hydrogen. Hyperconjugation are of three types: (i) s(C-H), p-conjugation. (iii) s(C-H), positive charge conjugation iv) s(C-H), odd electron conjugation The hyperconjugation may be represented as Number of resonating structures due to hyperconjugation = (n + 1) where n is the number of a-hydrogen. Greater is the number of such forms, more is the stability of the species under considersation. Which of the following carbocations will show highest number of Hyperconjugation forms?

The equation of Schroedinger for the hydrogen atom in the time-independet, non-relativistic form is a partial differential equation involving the position coordinates (x, y and z). The potential energy term for the proton-electron system is spherically symmetric of the form -1//4pi in_(0) xx (e^(2)//r) . THus it is advantages to change over from the cartesian coordinates (x,y and z) to the spherical polar coordinates, (r, theta and phi ). In this form the equation become separable in the radial part involving r and the angular part involving theta and phi . The probability of locating the electron within a volume element d tau = 4pi r^(2)dr is then given |Psi|^(2)(4pir^(2)dr) , where Psi is a function of r, theta and phi . With proper conditions imposed on Psi , the treatment yields certain functions, Psi , known as atomic orbitals which are solutions of the equations. Each function Psi correspods to quantum number n, l and m, the principal, the azimuthal and the magnetic quantum number respectively, n has values 1, 2, 3,...., l has values 0, 1, 2, ....(n-1) for each value of n and m (n-1) for each value of n and m (m_(l)) has values =1, +(l+1),...1,0,-1,-2...-l i.e., (2l+1) values for each value of l. In addition a further quantum number called pin had to be introduced with values +-1//2 . Any set of four values for n, l , m and s characterizes a spin orbital. Pauli.s exclusion principle states that a given spin orbital can accomodate not more than electron. Further the values l = 0, l=1, l=2, l=3 are designated s,p,d and f orbitals respectively. It is a basic fact that any two electrons are indistinguishable. 3 electrons are to be accomodated in the spin orbitals included under the designated 2p, conforming to the Pauli principle. Calculate the number of ways in which this may be done.

The equation of Schroedinger for the hydrogen atom in the time-independet, non-relativistic form is a partial differential equation involving the position coordinates (x, y and z). The potential energy term for the proton-electron system is spherically symmetric of the form -1//4pi in_(0) xx (e^(2)//r) . THus it is advantages to change over from the cartesian coordinates (x,y and z) to the spherical polar coordinates, ( r, theta and phi ). In this form the equation become separable in the radial part involving r and the angular part involving theta and phi . The probability of locating the electron within a volume element d tau = 4pi r^(2)dr is then given |Psi|^(2)(4pir^(2)dr) , where Psi is a function of r, theta and phi . With proper conditions imposed on Psi , the treatment yields certain functions, Psi , known as atomic orbitals which are solutions of the equations. Each function Psi correspods to quantum number n, l and m, the principal, the azimuthal and the magnetic quantum number respectively, n has values 1, 2, 3,...., l has values 0, 1, 2, ....(n-1) for each value of n and m (n-1) for each value of n and m (m_(l)) has values =1, +(l+1),...1,0,-1,-2...-l i.e., (2l+1) values for each value of l. In addition a further quantum number called pin had to be introduced with values +-1//2 . Any set of four values for n, l , m and s characterizes a spin orbital. Pauli.s exclusion principle states that a given spin orbital can accomodate not more than electron. Further the values l = 0, l=1, l=2, l=3 are designated s,p,d and f orbitals respectively. How many spin orbitals are there corresponding to n = 3?