Chemistry
Solutions and pH Chemistry
400 Questions
Solutions and pH chemistry focus on the acidity or alkalinity of various substances, from human urine to acidic soils. Questions involve titration calculations, molarity determination, and understanding mole fractions. This topic is a staple in the chemistry sections of state and national level competitive exams.
Calculating solution molarityMole fraction calculationpH value interpretationAcidic soils and pHTitration and neutralization
Solutions and pH Chemistry Questions
B
Correct answer
Explanation
Pure distilled water has a pH of exactly 7, which is considered neutral on the pH scale (0-14). The pH scale measures acidity (below 7) and alkalinity (above 7). Option B is correct. A pH of 8 would be slightly basic, while 6 and 5 would be acidic.
D
Correct answer
Explanation
Acid rain typically has a pH between 4 and 6, which is below the neutral pH of 7. This acidity comes from sulfur dioxide and nitrogen oxides reacting with water in the atmosphere to form sulfuric and nitric acids.
D
Correct answer
Explanation
To balance Al(OH)₃ + 3HCl → AlCl₃ + 3H₂O, we need 3 H₂O molecules. Balancing: Al(1), Cl(3), O(3 on each side), H(6 on each side). The coefficient 3 ensures hydrogen and oxygen atoms are balanced.
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acidic
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basic
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alkaline
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neutral
A
Correct answer
Explanation
On the pH scale, values below 7 are acidic, 7 is neutral, and above 7 are basic/alkaline. A pH of 2.5 is strongly acidic, indicating a high concentration of H⁺ ions.
B
Correct answer
Explanation
For solutions where the density of water is approximately 1 g/mL, 1 gram of mass occupies 1 milliliter of volume. This is a standard conversion used in chemistry and medicine when dealing with aqueous solutions.
C
Correct answer
Explanation
Orange juice typically has a pH between 3.3 and 4.2 due to its citric acid content. A pH of 3.5 is the most accurate among the given options. Note that option D (15.5) is impossible since the pH scale only ranges from 0 to 14.
A
Correct answer
Explanation
On the pH scale of 0-14, acids have pH values below 7, bases have pH values above 7, and 7 is neutral. The lower the pH, the stronger the acid. This is a fundamental chemical property.
B
Correct answer
Explanation
Bases have pH levels above 7, not below 7. The pH scale ranges from 0-14, with acids below 7 (0-6.99), neutral at 7, and bases above 7 (7.01-14). Substances like soap (pH ~10) and bleach (pH ~13) are bases with pH above 7.
B
Correct answer
Explanation
The sum of pH and pOH is always 14.0 at 25°C for any aqueous solution. This relationship comes from the water dissociation constant (Kw = [H+][OH-] = 1.0 × 10^(-14) at 25°C). It's a fundamental concept in acid-base chemistry.
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Oats - 5.0 - 7.5 pH
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Cotton - 6.0 - 7.5 pH
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Bean - 6.0 -8.0 pH
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Potato - 4.5 - 6.5 pH
A
Correct answer
Explanation
pH stands for potential of hydrogen and is a logarithmic scale used to specify the acidity or basicity of an aqueous solution, directly measuring the concentration of hydrogen ions (H+). Therefore, the statement is true.
D
Correct answer
Explanation
Lemon juice is acidic due to the presence of citric acid, with a typical pH range of 2-3, making option D the correct choice. pH 7 represents neutral substances like pure water, pH 9 indicates a basic solution, and pH 1 would be extremely acidic like stomach acid, which is far more acidic than lemon juice.
A
Correct answer
Explanation
Pure water has a pH of 7, which is neutral on the pH scale (0-14). Values below 7 are acidic, above 7 are basic. pH 10 would be alkaline, 0 strongly acidic, and 14 strongly basic.
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Gum
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Gelatin
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Starch
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Metal sulfides
D
Correct answer
Explanation
Sols of metals, e.g. gold sol, platinum sol, etc. and the sols of insoluble substances such as metal sulfides and oxides are some examples of lyophobic sols.
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158 min
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15.80 min
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3.90 min
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39 min
A
Correct answer
Explanation
15.80 min: Generation time (G) = total time (t)/{3.3 log (final number of cells)/(initial number of cells)}.