Answer
101101010011110111111000
Work Step by Step
You can convert the hexadecimal number to binary by converting each individual digit to the 4 bit binary representation in order.
$B = 1011, 5 = 0101, 3 = 0011, D = 1101, F = 1111, 8 = 1000$
Giving you the binary number
$101101010011110111111000$