Electrical conductivity (specific conductance): defined as the reciprocal of resistance of a 1 cm cube of liquid at a specified temperature. Approximately what is the conductivity of distilled water in micro mho per cm?

Introduction / Context:
Conductivity (specific conductance) quantifies a liquid’s ability to carry electric current and is widely used to assess water purity, ion content, and process quality. Distilled water has very low ionic content and therefore very low conductivity.

Given Data / Assumptions:

• Definition: Conductivity is the reciprocal of resistance of a 1 cm × 1 cm × 1 cm liquid sample, often reported as micro mho/cm (equivalent to microsiemens/cm).
• Sample: fresh distilled water, equilibrated with minimal CO2.

Concept / Approach:
Ultra-pure water approaches 0.055 micro mho/cm (18.2 MΩ·cm), but ordinary laboratory “distilled water” typically reads around 0.5–2 micro mho/cm because it absorbs CO2 and picks up trace ions from containers and air. A representative textbook value is about 1 micro mho/cm, reflecting practical (not ultra-pure) conditions.

Step-by-Step Solution:
Recall that higher dissolved ions → higher conductivity; pure water is near zero.Recognize typical lab-distilled water ≈ 1 micro mho/cm.Choose 1 micro mho/cm as the best estimate among the options.

Verification / Alternative check:
Handheld meters commonly show 0.5–2 micro mho/cm for freshly prepared distilled water; ultrapure deionized water shows ~0.055 micro mho/cm, consistent with the reasoning above.

Why Other Options Are Wrong:
50 or 100 micro mho/cm: Far too high; those values indicate significant ionic content.10 micro mho/cm: More like very clean tap or lightly treated water, not distilled.0.1 micro mho/cm: Approaches ultrapure water specifications rather than ordinary distilled.

Common Pitfalls:
Confusing “distilled” with “ultrapure DI”; mixing legacy micro mho/cm units with SI microsiemens/cm without converting.

Final Answer:
1 micro mho/cm