Article Detail Which is the lightest gas ? Answer: Hydrogen Similar Questions : 1. Which is longest tributary river of India ? Answer: Yamuna 2. Which is the Densest populated State of India ? Answer: West Bengal 3. Which is the largest epic in world ? Answer: Mahabharat 4. Which is Longest national highway of India ? Answer: NH-7 ( Varanasi to Kanyakumari - 2,369 km) 5. Which is longest river of South India ? Answer: Godavari 6. Which is the brightest planet ? Answer: Venus 7. Which is tallest statue in world ? Answer: Spring Temple Buddha located in the Zhaocun township of Lushan County, Henan, China Read more from - Longest and Largest