Let, a = 0.212112111211112
And, b = 0.232332333233332...
Clearly, a < b because in the second decimal place a has digit 1 and b has digit 3 If we consider rational numbers in which the second decimal place has the digit 2, then they will lie between a and b.
Let,
x = 0.22
y = 0.22112211...
Then,
a < x < y < b
Hence, x, and y are required rational numbers.