States of Matter

Hydrofluoric acid is a highly corrosive chemical solution that readily reacts with and dissolves glass, silica, and silicate materials. Because of this unique property, it must be stored in plastic containers like polyethylene.

While some bottled water has been found to contain contaminants, the specific claim that exactly one-third contains synthetic organic chemicals, bacteria, and arsenic together is not supported by research. Studies show varying contamination levels, but this precise statistic is exaggerated.

Unit operations involve physical changes (like filtration, distillation, heat transfer) without chemical reactions. Unit processes involve chemical changes (like combustion, polymerization) where chemical composition changes. Option E correctly combines these definitions: unit operations are physical-only, unit processes are chemical-focused changes.

Water on the Moon exists primarily as thin films of water molecules trapped in lunar dust and minerals, not as liquid bodies like rivers or wells. This water was confirmed by missions like Chandrayaan-1 in 2009. Options A and C suggest flowing water bodies which don't exist on the Moon, while 'gel' is not how lunar water is found.

Sodium is an alkali metal that reacts violently with water, producing hydrogen gas and heat. The heat ignites the hydrogen, causing an explosion. This is a characteristic property of Group 1 metals.

Gasoline is a mixture of various petroleum hydrocarbons, and its freezing point is very low, typically around minus 40 to minus 60 degrees Celsius. Under extreme cold conditions, it can indeed freeze or turn slushy.

Mercury is the only metal that exists in liquid state at standard room temperature (20-25°C). Bromine is the only other non-metal element that is liquid at room temperature.

Liquid water cannot exist on Mars' surface primarily because of the extremely low atmospheric pressure, which is about 1% of Earth's. At such low pressure, water either boils away immediately or remains frozen, making stable liquid water impossible on the surface.

Heavy water uses deuterium (D), a heavy isotope of hydrogen, instead of regular hydrogen. The formula is D2O. H2O is regular water, H2O2 is hydrogen peroxide, and T2O uses tritium.

Hydrogen is an element consisting of only hydrogen atoms (H₂ molecules). Water (H₂O) contains hydrogen and oxygen atoms. Milk is a complex mixture of water, fats, proteins, and sugars. Air is a mixture of nitrogen, oxygen, carbon dioxide, and other gases.

Pure water has the highest specific heat capacity (4.18 J/g°C) and thermal conductivity among the options, enabling it to absorb heat most rapidly. Salt water has slightly lower specific heat capacity. Motor oil has much lower heat capacity and thermal conductivity, making it the slowest coolant.

Dry ice is solid carbon dioxide (CO2). When dry ice sublimates, it transitions directly from solid to gas without becoming liquid, producing carbon dioxide gas. This is why dry ice 'disappears' when left at room temperature - it converts to invisible CO2 gas.

A firecracker explosion involves combustion reactions that produce new substances (gases, light, heat), making it a chemical change. Chopping, melting, and boiling are physical changes that don't create new chemical substances.

The proverb is Blood is thicker than water, meaning family bonds and relationships are stronger than friendships or other connections. The phrase emphasizes the importance of kinship ties.

Barbados is widely recognized as the birthplace of rum, with sugarcane plantations and distilleries operating since the 17th century. The island became synonymous with rum production, leading to the nickname 'Barbados water' in certain contexts. Pina colada is a cocktail containing rum, not the spirit itself, while vodka and gin originate from different regions and base ingredients.