Which one of the following gives the highest amount of hydrogen ions (H⁺)?
- A.Sodium hydroxide solution
- B.Milk of magnesia
- C.Lemon juice
- D.Gastric juice
Correct answer
Explanation
The correct answer is D, Gastric juice. It contains hydrochloric acid and has a pH of about 1.5 to 2, the lowest of the four, so it has the most hydrogen ions.
pH measures hydrogen ion concentration on a scale where each step down means ten times more H⁺ ions. The stomach lining secretes dilute hydrochloric acid, which kills germs in food and activates the enzyme pepsin for digesting proteins. A mucus layer protects the stomach wall from its own acid; when too much acid is made, people take antacids.
A, sodium hydroxide solution, is a strong base with a pH near 13–14, so it has very few hydrogen ions.
B, milk of magnesia (magnesium hydroxide), is a mild base of pH about 10, used as an antacid.
C, lemon juice, is acidic because of citric acid, but its pH is about 2 to 2.5, higher than that of gastric juice.
Exam tip: lower pH = more H⁺; gastric juice (pH ~1.5) is more acidic than lemon juice (pH ~2.2).
Practice Questions
View allRecently, there was a growing awareness in our country about the importance of Himalayan nettle (Girardinia diversifolia) because it is found to be a sustainable source of
- A.anti-malarial drug
- B.biodiesel
- C.pulp for paper industry
- D.textile fibre
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The Himalayan nettle yields a strong natural fibre that can be spun and woven into cloth. Girardinia diversifolia, known as Himalayan giant nettle or allo, is a stinging shrub that grows wild in the moist forests of the Himalayas, including Uttarakhand, Himachal Pradesh and the North-east, as well as Nepal.
Read the full explanation →Which of the following statements are correct regarding the general difference between plant and animal cells ? 1. Plant cells have cellulose cell walls whilst animal cells do not. 2. Plant cells do not have plasma membrane unlike animal cells which do. 3. Mature plant cell has one large vacuole whilst animal cell has many small vacuoles. Select the correct answer using the code given below:
- A.1 and 2 only
- B.2 and 3 only
- C.1 and 3 only
- D.1,2 and 3
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Read the full explanation →Consider the following statements : 1. In tropical regions, Zika virus disease is transmitted by the same mosquito that transmits dengue. 2. Sexual transmission of Zika virus disease is possible. Which of the statements given above is/are correct ?
- A.1 only
- B.2 only
- C.Both 1 and 2
- D.Neither 1 nor 2
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Read the full explanation →What is the importance of using Pneumococcal Conjugate Vaccines in India ? 1. These vaccines are effective against pneumonia as well as meningitis and sepsis. 2. Dependence on antibiotics that are not effective against drug-resistant bacteria can be reduced. 3. These vaccines have no side effects and cause no allergic reactions. Select the correct answer using the code given below :
- A.1 only
- B.1 and 2 only
- C.3 only
- D.1, 2 and 3
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Read the full explanation →Which one of the following is NOT true for bleaching powder?
- A.It is used as a reducing agent in chemical industries
- B.It is used for bleaching wood pulp in paper factories
- C.It is used for disinfecting drinking water
- D.It is used for bleaching linen in textile industry
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Bleaching powder is an oxidising agent, not a reducing agent, so this statement is the false one. Bleaching powder, calcium oxychloride (CaOCl₂), is made by passing chlorine gas over dry slaked lime, Ca(OH)₂.
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