1. The electrolyte used is a solid polymer membrane that conducts protons.
2. Platinum is commonly used as a catalyst at both anode and cathode.
3. The operating temperature typically exceeds 500°C to ensure fast kinetics.
4. Water is formed at the cathode during normal operation.
Which of the statements given above are correct?
Statement 1 – Correct: LT-PEM fuel cells use a solid polymer electrolyte membrane (such as Nafion) that selectively conducts protons from anode to cathode.
Statement 2 – Correct: Precious metal catalysts, especially platinum, are commonly employed at both the anode and cathode to facilitate electrochemical reactions.
Statement 3 – Incorrect: LT-PEM fuel cells operate at relatively low temperatures, typically around 50–100°C; temperatures exceeding 500°C are characteristic of high-temperature fuel cells, not LT-PEM.
Statement 4 – Correct: At the cathode, protons combine with electrons and oxygen to form water as a reaction product.
Option (c) – Correct: LT-PEM fuel cells provide a high power-to-weight ratio, compact system design, and rapid start-up due to their low operating temperature, making them well-suited for transport and marine applications.
Option (a) – Incorrect: PEM fuel cells require high-purity hydrogen, as impurities can poison the catalyst and degrade performance.
Option (b) – Incorrect: High-temperature operation enabling waste-heat recovery is characteristic of solid oxide fuel cells (SOFCs), not PEM fuel cells.
Option (d) – Incorrect: PEM fuel cells critically depend on catalysts such as platinum to drive electrochemical reactions at both electrodes.
Reason (R): In PEM fuel cells, oxygen combines with protons and electrons at the cathode to form water.
Assertion – True: PEM fuel cells generate electricity through electrochemical reactions that produce only water and a small amount of heat as by-products, without emitting greenhouse gases during operation.
Reason – True and explains Assertion: At the cathode, oxygen reacts with protons that have passed through the membrane and electrons flowing through the external circuit, forming water. This reaction directly explains why water is the sole emission.
Option (b) – Correct: The Rio Grande, known as Río Bravo in Mexico, forms a substantial stretch of the international boundary between Mexico and the United States, particularly along the border between Texas and northern Mexican states such as Chihuahua and Coahuila.
Option (a) – Incorrect: Cuba is an island nation in the Caribbean Sea and does not share any land boundary with Mexico.
Option (c) – Incorrect: Belize lies to the southeast of Mexico, bordering the Yucatán Peninsula, not to the north.
Option (d) – Incorrect: Mexico is a full member of the United Nations and was among its founding members in 1945.
1. The festival is held in Majuli to commemorate Asia’s first protected royal bird sanctuary.
2. Charaichung sanctuary was established in 1633 AD during the reign of Ahom king Swargadeu Pratap Singha.
3. Majuli is located on the Barak River and is the largest inhabited river island in Asia.
Which of the statements given above are correct?
Statement 1 – Correct: The Charaichung Festival is organised in Majuli to commemorate Asia’s first protected Royal Bird Sanctuary, Charaichung.
Statement 2 – Correct: The Charaichung sanctuary was established in 1633 AD during the reign of the Ahom king Swargadeu Pratap Singha.
Statement 3 – Incorrect: Majuli is located in the Brahmaputra River, not the Barak River, and it is recognised as the world’s largest river island.