The number of $\mathrm{\pi }$ bonds and $\mathrm{\sigma }$ bonds in the following structure is :

1. 6, 19

2. 4, 20

3. 5, 19

4. 5, 20

The electronic configurations of three elements, A, B, and C are given below.  

A 1s² 2s² 2p⁶
B 1s² 2s² 2p⁶ 3s² 3p³
C 1s² 2s² 2p⁶ 3s² 3p⁵

The molecular formula of the compound formed from B and C will be 

1. $\mathrm{BC}$

2. ${\mathrm{B}}_2\mathrm{C}$

3. ${\mathrm{BC}}_2$

4. ${\mathrm{BC}}_5$

Match the items given in Column I with examples given in Column II.

Codes

Among the following, the correct statements about ${\mathrm{CO}}_3^{2- }$

Choose the correct option

1. (a), (b)

2. (b), (c)

3. (c), (d)

4. (b), (d)

The incorrect statements among the following are-

1. (a), (b)

2. (b), (c)

3. (c), (d)

4. (b), (d)