The orbital angular momentum of an electron is 2s & orbital is

For $s$-subshell $l = 0$

Orbital angular momentum $( mvr ) = \dfrac{h}{2\pi}\sqrt{l ( l + 1 )}$

For $2s$ orbital, $l$ (azimuthal quantum number) $= 0$
$∴$ orbital angular momentum $= \dfrac{h}{2\pi}\sqrt{0 ( 0 + 1 )}$

$= \dfrac{h}{2\pi}\sqrt{0} = 0$

Thus, the orbital angular momentum of an electron in $2s$ -orbital is& Zero.