Question

19. The number of sigma bonds and pi-bonds in CH3-CH=CH2 are respectively
(A) 7,1 (B) 8,1
(C) 1.8 (D) 2,7
20. Which one is an electrophile?
(A) AICI3 (B) C2H5NH2
(C) CN (D) C2H5OH
21. The hybridized orbitals employed to explain the geometry of 13 - are :
(A) sp2 (B) sp3d2
(C) sp3 (D) sp3d
​

Answer 1

Q.19. Option B) is the correct answer.

single bond= sigma bonds.

double bond = one sigma + one pi bond

Here total single bonds are 7 + 1 sigma bond from double bond so total sigma bond is 8.

and only one double bond is there so one pi bond is there.

Q.20 option A) is the correct answer.

electrophiles are the electron deficient species or we can say they can easily accept the electrons.

Look at the image here after bonding also Al is only having 6 electrons in its octet instead of 8 electrons. so it is an electrophile.

I didn't get your question 21.

check it if there is any mistake in it.