In the above chemical reaction sequence "$$\mathrm{A}$$" and "$$\mathrm{B}$$" respectively are

The maximum number of orbitals which can be identified with $$\mathrm{n}=4$$ and $$m_l=0$$ is _________.

Number of compounds / species from the following with non-zero dipole moment is _________.

$$\mathrm{BeCl}_2, \mathrm{BCl}_3, \mathrm{NF}_3, \mathrm{XeF}_4, \mathrm{CCl}_4, \mathrm{H}_2 \mathrm{O}, \mathrm{H}_2 \mathrm{~S}, \mathrm{HBr}, \mathrm{CO}_2, \mathrm{H}_2, \mathrm{HCl}$$

The total number of 'sigma' and 'pi' bonds in 2-oxohex-4-ynoic acid is ______.