Can I buy a property in cash?

Yes but it should be for less than 2 lacs. 269ST.
You cannot make advance payment of Rs. 20000 or more. 269SS.
Depreciation will not be allowed in respect of cash component.

Amount of property is 25 Lacs around then can I use it for buying that's black income completely.

It's difficult...
As such nowadays.

@ Mr. Mukesh Parmar
You can not buy Property by giving total value in Cash. If you are making agreement of Property, than that total agreement value you have to pay in cheque only.( Yes, less than 2,00,000 in cash allowed).
So, if you purchase Property for Rs. 25 lakh, but agreement is of Rs. 15 lakh, than required to give 15 lakh in cheque and 10 in Cash.

Thanks Sagar for valuable suggestion

Most welcome.....

Cash in 10 lacs can be paid only if u spread the payment in cash over 6 days.

@ Subyasachi ji

Cash in 10 Lakhs can not be paid, whether you spread the payment in cash over 6 days or any number of days, because it's relating to single transaction.(i.e property)

Yes, you can give in "black" any amount.