The first option is correct. have fun in earth science i love astronomy!! :)
Answer:
A. Soaps react with ions in hard water to create a precipitate.
B. Soaps are both hydrophobic and hydrophilic.
D. Soaps should be weakly alkaline in solution.
Explanation:
A. Hard water contains <u>magnesium and calcium minerals</u> like calcium and magnesium carbonates, sulfates and bicarbonates. As soon as these minerals come in contact with soap their ions like Mg²⁺ & Ca²⁺ form precipitates.
B. Soap are both hydrophilic and hydrophobic. They reason why they exhibit both the properties is really important for their functionality. The hydrophobic part of soap makes interaction with oil/dust particles while the hydrophilic part makes interaction with water. When the cloth is rinsed the dirt/soap particles are removed from the dirty clothes thereby making them clean.
C. Soaps have alkaline pH i.e. more than 7 that is why they have bitter taste.
Answer:
a.
△H=−72 kcal
The energy required for production of 1.6 g of glucose is [molecular mass of glucose is 180 gm]
b.

The iron(III) ions and chloride ions remain aqueous and are spectator ions in a reaction that produces solid barium sulfate.
Explanation:
Lime is added to lower the acidity of lakes when pH levels go too low.
Acidic environment is harmful to aquatic ecosystems. Acidity causes some minerals, such as phosphorus and calcium, in the water to become unavailable to aquatic organisms like plants and fishes ( This means the water hardness is reduced). The low nutrients cause stress and death in the aquatic environment lowering biodiversity. Applying lime raises the pH to neutral levels and improves the health of the aquatic life in the lake. This also improves economic activities in the lake like fishing.
Learn More:
For more on acidicity of lakes check out;
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