The easiest way to approximate ph level is through the ph paper measurement system because using pH paper would be best for doing a quick measurement in the field. It does not essentially need to be calibrated or standardized and the papers make available an instant estimate.
I believe the correct answer from the choices listed above is option B. A chemical formula written above or below the yield sign indicates <span>that the substance is used as a catalyst. I am certain with this answer. Hope this helps. Have a nice day.</span>