Which one-word substitute best expresses the phrase "causing a burning sensation like that of hot liquid on the skin"?

Introduction / Context:
This vocabulary question asks for a precise one-word substitute for a descriptive phrase about a particular kind of burning sensation. The phrase mentions hot liquid on the skin, which is a key clue. To answer correctly, you need to distinguish between several temperature related adjectives and identify the one commonly used for burns caused by hot liquids or steam.

Given Data / Assumptions:

• The phrase to be replaced is causing a burning sensation like that of hot liquid on the skin.
• Option A piping often appears in the expression piping hot, but is not limited to burns on skin.
• Option B igneous relates to fire and rock formations, especially in geology.
• Option C sizzling describes the sound and appearance of something very hot, such as food in a pan.
• Option D scalding is used for injuries or heat caused by hot liquids or steam.

Concept / Approach:
The word scalding is specifically associated with burns caused by hot water, milk, oil, or steam. In everyday English, a scald is a burn from hot liquid; to scald means to burn with hot liquid. This matches the phrase in the question almost exactly. Piping hot and sizzling hot can be used to describe very hot food, but they focus on the level of heat and sound, not the specific type of skin injury. Igneous belongs to the technical vocabulary of geology and is not used for sensations on the skin.

Step-by-Step Solution:
Step 1: Focus on the key detail: like that of hot liquid on the skin. This suggests a particular type of burn.Step 2: Recall that scalding is the standard adjective for something hot enough to cause a scald, that is, a burn from liquid or steam.Step 3: Evaluate piping; although we can say piping hot tea, piping alone does not capture the idea of burning on the skin and is not usually used as a standalone adjective for sensation.Step 4: Evaluate sizzling; it usually describes sound and appearance when something cooks, not the effect on human skin.Step 5: Evaluate igneous; this is clearly a specialised geological word for rocks formed from molten magma and is irrelevant here. Therefore, scalding is the only accurate and context appropriate choice.

Verification / Alternative check:
Imagine a safety warning on a kettle or a pot: Warning: scalding water. This is standard wording that warns of burns from hot liquid. We also say scalding tea, scalding soup, or a scalding shower when the water is dangerously hot to the skin. You would not normally say igneous tea or sizzling tea in this context. While piping hot soup is possible, it focuses on the soup temperature rather than the explicit possibility of skin burns. The legal and medical term for such burns is scald, which confirms scalding as the correct adjective.

Why Other Options Are Wrong:
Piping is incomplete without hot and even then does not directly mean burning the skin. Igneous is restricted to rocks and geological processes. Sizzling evokes the sound and look of food in contact with very high heat, like meat on a grill, and is not standard for describing how hot liquid burns skin. None of these options align as precisely with the idea of a burning sensation caused by hot liquid on the skin as scalding does.

Common Pitfalls:
Because students often see the phrase piping hot in reading passages, they may be drawn to piping without noticing that the question highlights skin sensation and hot liquid, which is the specific domain of scalding. To avoid this, always match not just the general topic (heat) but the exact situation described (burn from hot liquid). This is a typical pattern in one-word substitution questions.

Final Answer:
The best one-word substitute is scalding, so option D is correct.