5. how many subnets are possible in a network with a /19 cidr?

8192

Explanation:

The question is pretty general. However, I will try to explain it in my way.

An IP address consists of 32 bit. It is always divided in two portion, net id and host id. Net id is a kind of identification while host id bits includes the possible number of host in the network of specific id.

My assumption is that you are using the classless CIDR.

In that case the first 19 bits would be the net id or identification of the network. Therefore, the net id would be 11111111.11111111.11100000.00000000

Or 255.255.224.00

Now, if we want to add a subnet in this IP, we can utilize the remaining bits from the host id. We are left with 13 bits in host id so the number of subnets will be depending on how many bits we will be using in host id with

.  

In this equation, x represents the number of bits used to create the subnets.

So, maximum number of subnets would be