Article Detail Which is the lightest gas ? Answer: Hydrogen Similar Questions : 1. Which Indian state is having longest coastline ? Answer: Gujrat 2. Which is the largest desert in India ? Answer: Thar (Rajasthan) 3. Which is longest tributary river of India ? Answer: Yamuna 4. Which is the Densest populated State of India ? Answer: West Bengal 5. Which state is largest by Population ? Answer: Uttar Pradesh 6. Which is the shortest day in the year ? Answer: December 22 7. Which is largest Dome in India ? Answer: Gol Gumbaz (Karnataka) Read more from - Longest and Largest