Hi
Yes, you will be liable to pay capital gain tax. It would be a long term capital gain which is chargeable to tax @20% plus cess and surcharge, if any.
Capital gains shall be calculated by reducing indexed cost of acquisition from the sale proceeds.
You may claim capital gain tax exemption by reinvesting the capital gains into a new residential house property under section 54 or section 54 EC eligible bonds within the stipulated time limits