Applicability of income tax on land purchased 22 years back

Sir, my mother has brought a vacant land in Bangalore in 1995. All most 22 years land. Now we are trying to sell the land for Rs. 30,00,000/- to one of the purchaser. My mother age is approx 55 - 60 years. Please inform whether we need to pay income tax. if my mother divides the property amount whether even we need to pay tax. tax. Also please inform how to exempt tax. We are very poor and trying to sell land for marriage of my 2 siblings. if we divide / gift the amount for them the income is applicable / exempted. Please inform.