What's A 33 Bit Subnet Mask?

Subnets are concerned with the allocation of IPs and breaking them up  so that they can be scalable according to todays internet device requirements. Subnet masks can be variable-length (VLSM). I imagine that a 33 bit mask would be used to allow for more flexible allocation of IP's to the network administrator.

A 33 bit subnet mask is somewhat like a UFO or a three dollar bill - there isn't any such thing.  A subnet mask has only 32 bits unless you are discussing IPv6 where it could have as many as 128 bits.  I suspect you may have misunderstood the number.

Once I came across 33 bit subnet mask & i was confused. Then i understood that
if we calculate mask for some range of IP addresses & this range doesnt come in any possible subnet i.e mask doesnt match any of 32 masks then mask bits = 33 is returned;