Is an alcohol which contains 100 percent ethanol is fit to drink?

If you dilute it. Otherwise it will damage the lining of your mouth, throat, stomach and probably your small intestine.

200-proof (100%) alcohol is generally only found in laboratories, as getting all the water out of alcohol is expensive. Most 180-190 proof beverage alcohol, which can be purchased in liquor stores, is used to "spike" punches and other mixtures. The strongest liquors are in the 150-proof range (75%), and they are also normally used for mixed drinks.

Remember that alcohol is actually a poison, and in high concentrations it is really hard on living cells, especially mucous membranes.