When you are selling the residential house for Rs. 1 Cr, the long term capital gain (LTCG) will be the selling price less the cost of acquisition. We need to know the cost of acquisition and the date of acquisition for computing the LTCG.
The exemption of LTCG u/s 54 is available if you are acquiring a residential house, which appears to be available in your case.
The exact amount of LTCG and the exemption will depend upon the cost and year of acquisition.
In the case of sale of plot of land, you can claim exemption u/s 54F, only if you are investing entire sale proceeds in the acquisition of a new residential house, subject to fulfillment of conditions specified therein. One important condition is that you cannot have another residential house. So you may not get exemption u/s 54F. Exemption u/s 54 will not be available to you, as the property sold is not a residential house but only a plot. In this case, I suggest that you can claim u/s 54EC by investing entire amount in Capital Gain bonds, which has a lock in period of 3 years, after which the money can be used by you in whatever manner you like.