Correct Answer: C

Rationale: The correct property of an acid is that it 'reacts with bases.' Acids are known for their ability to react with bases to form salts and water through a process called neutralization. This unique reaction distinguishes acids from other substances and is a fundamental characteristic of acids in chemistry. Choices A, B, and D are incorrect. Acids do not have a bitter taste (Choice A), a slippery feel (Choice B), or a sweet taste (Choice D). These properties are not typical of acids and may lead to confusion if associated with acids.

Correct Answer: A

Rationale: A synthesis reaction involves the combination of two or more reactants to form a single product. This type of reaction is characterized by the merging of substances to create a more complex compound. In a synthesis reaction, the reactants bond together to form a new product, making it the correct choice for this scenario. Combustion reactions involve the rapid combination of oxygen with another substance, resulting in the release of energy in the form of heat and light. Decomposition reactions entail the breakdown of a compound into simpler substances, often through the application of heat or electricity. Double displacement reactions involve the exchange of ions between two compounds, leading to the formation of two new compounds.

Correct Answer: A

Rationale: The correct answer is 'Silicon.' Silicon is a metalloid, which means it has properties of both metals and nonmetals. It is commonly used in electronic devices due to its semiconductor properties. Lead (Choice B) is a metal, Helium (Choice C) is a noble gas, and Aluminum (Choice D) is a metal.

Correct Answer: D

Rationale: During photosynthesis, plants and other organisms convert carbon dioxide and water into glucose and oxygen. Glucose is a carbohydrate produced by plants as a result of photosynthesis, serving as their main source of energy. Oxygen is released as a byproduct of this process, while carbon dioxide and water are the raw materials used to produce glucose. Therefore, the correct answer is 'Glucose,' making it a vital product of the photosynthesis process. Choices A, B, and C are incorrect as carbon dioxide and water are the reactants needed for photosynthesis, and oxygen is released as a byproduct.

Correct Answer: B

Rationale: To convert Kelvin (K) to Celsius (°C), you subtract 273.15 from the Kelvin value. Therefore, 119 K - 273.15 = -154.15°C. The negative sign indicates that the temperature is below freezing. When rounded to the nearest whole number, -154.15°C is approximately -154°C. Choice A and Choice C are incorrect as they do not reflect the correct conversion from Kelvin to Celsius. Choice D is incorrect as it corresponds to the freezing point of water in Celsius, not the conversion of 119 K.