Article Detail Which is the lightest gas ? Answer: Hydrogen Similar Questions : 1. Which is smallest planet ? Answer: Mercury 2. Which is tallest statue in world ? Answer: Spring Temple Buddha located in the Zhaocun township of Lushan County, Henan, China 3. Which is longest river of South India ? Answer: Godavari 4. Which is the longest day in the year ? Answer: June 21 5. Which is the longest River in the World ? Answer: Nile 6. Which is the largest Mosque in World ? Answer: Masjid al Haram (Saudi Arabia) 7. Which is largest continent ? Answer: Asia Read more from - Longest and Largest