Pressure unit conversions (single incorrect option): Choose the one conversion that is NOT correct.

Introduction / Context:
Accurate pressure conversions are indispensable in vacuum systems, gas-phase reactions, and equipment specifications. This item checks familiarity with common engineering units and prevents order-of-magnitude errors that could compromise design safety or data interpretation.

Given Data / Assumptions:

• Standard reference values near 1 atm.
• Use exact or conventional rounded constants widely accepted in engineering.

Concept / Approach:
Memorise or quickly derive the key equivalences: 1 atm ≈ 1.01325 bar; 1 bar = 100 kPa = 10^5 Pa; 1 mm Hg ≈ 1 torr ≈ 133.3 Pa. Evaluate each option against these anchors to identify the single incorrect statement.

Step-by-Step Solution:
Check (a): 1 atm = 760 mm Hg = 29.92 in Hg = 14.7 psi ≈ 1.01325 bar → correct.Check (b): 1 kPa = 100 bar → incorrect by eight orders of magnitude. Correct is 1 bar = 100 kPa (so 1 kPa = 0.01 bar).Check (c): 1 mm Hg = 1 torr ≈ 133.3 Pa → correct.Check (d): 1 bar = 10^5 Pa → correct by definition.

Verification / Alternative check:
From SI, 1 Pa = 1 N/m^2. The bar is a convenient non-SI unit defined as 10^5 Pa, making 1 bar exactly 100 kPa. Therefore, statement (b) is clearly wrong.

Why Other Options Are Wrong:
Options (a), (c), and (d) match accepted engineering constants and are widely used in handbooks and instrumentation.

Common Pitfalls:
Inverting bar–kPa relationships; mixing absolute and gauge pressures; over-rounding constants where precision matters.

Final Answer:
1 kPa = 100 bar