Explanation: Acids do not turn red litmus to blue; instead, they turn blue litmus paper red. Acids are sour in taste, corrosive in nature, and have a pH value less than 7. Therefore, the statement that acids turn red litmus to blue is incorrect.

Explanation: Water shows an unusual property known as anomalous expansion. Its density is maximum at 4°C. When cooled from higher temperatures, water contracts till 4°C, becoming denser. Below 4°C, it expands instead of contracting, so its density decreases. This property allows ice to float and prevents water bodies from freezing solid, protecting aquatic life during winters.

Explanation: Tuberculosis (TB) is not a viral disease; it is caused by a bacterium called Mycobacterium tuberculosis. In contrast, Polio, Swine flu, and Hepatitis are viral diseases caused by different types of viruses.

PINAKA is an indigenously developed Multi Barrel Rocket Launch (MBRL) system designed and produced by the Defence Research and Development Organisation (DRDO) of India. It is capable of firing a salvo of rockets to deliver explosive warheads over large areas with high accuracy. Pinaka is primarily used by the Indian Army for long-range artillery support and has a range of up to 75 km in its upgraded version (Pinaka Mk-II).

Other options (for context)

• Anti-submarine torpedo and research vehicle: Refers to underwater weapon systems, not related to Pinaka.
• Aircraft carrier: A large naval vessel capable of carrying aircraft; Pinaka is not a ship.
• Guided missile frigate submarine warship: Refers to naval warships, not a land-based rocket launcher.

Explanation: Asbestos is a group of naturally occurring fibrous silicate minerals once widely used in construction and insulation. When inhaled, asbestos fibers accumulate in the lungs and pleura, leading to inflammation and scarring over years. This chronic exposure can cause asbestosis (lung fibrosis) and mesothelioma — a deadly cancer of the membrane lining the lungs (pleura) or abdomen (peritoneum).

Explanation: The Sun produces its enormous energy through the process of nuclear fusion. In this process, hydrogen nuclei (protons) combine under extremely high temperature and pressure to form helium, releasing a tremendous amount of energy in the form of light and heat. The main fusion reaction in the Sun is the proton–proton chain. Unlike fission (splitting of nuclei), fusion combines light nuclei, and this is what powers all stars, including the Sun.

Explanation: When a car moves forward while rain is falling vertically, the rain appears to fall at an angle relative to the car’s motion. As a result, the raindrops strike the front windscreen of the car, not the rear screen. This is due to the relative velocity between the car and the falling rain.

Explanation: The blue colour of the sky is due to the scattering of sunlight by molecules and small particles in the Earth's atmosphere. Shorter wavelengths of light (blue and violet) are scattered more than longer wavelengths (red and yellow). Since our eyes are more sensitive to blue light, the sky appears blue.