Which of the following is correct regarding the pH scale?
A substance with a pH of 3 is two times more alkaline than a substance with a pH of 4.
A substance with a pH of 3 is two times more acidic than a substance with a pH of 4.
A substance with a pH of 3 is 10 times more acidic than a substance with a pH of 4.
A substance with a pH of 3 is 10 times more alkaline than a substance with a pH of 4.
The Correct Answer is C
The pH scale is a logarithmic scale that measures the acidity or alkalinity of a solution.
A solution with a pH of 7 is neutral, while a solution with a pH less than 7 is acidic and a solution with a pH greater than 7 is alkaline.
Because the pH scale is logarithmic, each whole number change in pH represents a tenfold change in acidity or alkalinity.
Therefore, a substance with a pH of 3 is 10 times more acidic than a substance with a pH of 4.
Choice A. A substance with a pH of 3 is two times more alkaline than a substance with a pH of 4 is not correct because it incorrectly states that the substance with a lower pH is more alkaline and also incorrectly states the magnitude of the difference in acidity or alkalinity.
Choice B. A substance with a pH of 3 is two times more acidic than a substance with a pH of 4 is not correct because it correctly states that the substance with a lower pH is more acidic but incorrectly states the magnitude of the difference in acidity.
Choice D. A substance with a pH of 3 is 10 times more alkaline than a substance with a pH of 4 is not correct because it incorrectly states that the substance with a lower pH is more alkaline.
Nursing Test Bank
Naxlex Comprehensive Predictor Exams
Related Questions
Correct Answer is A
Explanation
Melanin is a pigment produced by cells called melanocytes in the skin.
It protects the skin from ultraviolet (UV) radiation by absorbing and dissipating over 99.9% of absorbed UV radiation.
This helps to prevent DNA damage and other adverse effects of UV radiation on the skin.
Choice B. Perspiration is not correct because it is a fluid produced by sweat glands in the skin that helps to regulate body temperature, but it does not protect the skin from UV radiation.
Choice C. Sebum is not correct because it is an oily substance produced by sebaceous glands in the skin that helps to lubricate and protect the skin, but it does not protect the skin from UV radiation.
Choice D. Keratin is not correct because it is a fibrous protein that provides strength and durability to the skin, hair and nails, but it does not protect the skin from UV radiation.
Correct Answer is A
Explanation
A myocardial infarction, commonly known as a heart attack, occurs when blood flow decreases or stops in the coronary artery of the heart, causing damage to the heart muscle.
Choice B is incorrect because the aorta is not a blood vessel of the heart.
The aorta is the main artery that carries oxygenated blood from the heart to the rest of the body.
Choice C is incorrect because the pulmonary blood vessels are not affected by a myocardial infarction.
The pulmonary blood vessels carry deoxygenated blood from the heart to the lungs.
Choice D is incorrect because the vena cava is not a blood vessel of the heart.
The vena cava is a large vein that carries deoxygenated blood from the body to the heart.
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