Tag: what floats - what sinks

Questions Related to what floats - what sinks

The given sample of lathers easily with water, it is :

evs experiments with water water and its types hard and soft water what floats - what sinks

  1. hard water.

  2. soft water.

  3. permanent hard water.

  4. temporary hard water.

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Correct Option: B
Explanation:

Soft water is surface water that contains low concentrations of ions and in particular is low in ions of calcium and magnesium. Because soft water has few calcium ions, there is no inhibition of the action of soaps and no soap scum is formed in normal washing. It lathers easily with water. Similarly, soft water produces no calcium deposits in water heating systems.

A cloudy or milky appearance characterizes :

evs experiments with water water and its types hard and soft water what floats - what sinks

  1. soft water

  2. hard water

  3. chlorinated water

  4. both a and c

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Correct Option: B
Explanation:

An easy way in which water manifests its hardness is scaling i.e. forming deposits through calcification that clog plumbing. These scales are usually white because calcium and magnesium are the most common sources of hardness in water. In swimming pools, a cloudy or milky appearance characterizes hard water.

Permanent hardness of water can be removed by :

evs experiments with water water and its types hard and soft water what floats - what sinks

  1. boiling

  2. filtration

  3. adding washing soda

  4. both b and c

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Correct Option: C
Explanation:

Hardness of water can be of two types temporary and permanent hardness. Permanent hard water contains chlorides and sulphates of calcium and magnesium. It can be removed by adding washing soda.

A soap is :

evs experiments with water water and its types hard and soft water what floats - what sinks

  1. sodium or potassium salt of organic acid

  2. sodium salts of sulphonic acid

  3. both a and b

  4. chloride salts of organic and sulphonic acid

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Correct Option: A
Explanation:

Soap is the sodium and potassium salt of organic fatty acid. Soap reacts with hard water forming scum. They are derived from the treatment of tryglycerides with a strong base (saponification). Soaps are made by rendering fats from animal sources.

Sodium salts of sulphonic acid are :

evs experiments with water water and its types hard and soft water what floats - what sinks

  1. soap

  2. detergents

  3. hard water

  4. soft water

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Correct Option: B
Explanation:

Detergents are soap-like compounds which are used for cleaning purpose. They are sodium salts of long chain alkyl benzene sulphonic acids or sodium salts of long chain alkyl hydrogen sulphate, whereas, soaps are sodium salts of long chain carboxylic acids.

Washing soda soften both temporal and permanent hardness by :

evs experiments with water water and its types hard and soft water what floats - what sinks

  1. Dissolving salts

  2. Forming precipitate

  3. Forming soluble salts

  4. None of the above

Show answer
Correct Option: B
Explanation:

Permanent hard water can be made soft by adding sodium carbonate (also called washing soda) to it. This will soften both temporal and permanent hardness. In this chemical reaction, the calcium and magnesium ions react with sodium to form a precipitate.

Water which gives lather with soap easily is called as :

evs experiments with water water and its types hard and soft water what floats - what sinks

  1. soft water.

  2. hard water.

  3. distilled water.

  4. both A and B

Show answer
Correct Option: A
Explanation:

Water which gives lather with soap easily is called as soft water.

Which of the following is/are soluble in water?

evs experiments with water water and its types hard and soft water what floats - what sinks

  1. Ghee

  2. Curd

  3. Blood

  4. Sugar

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Correct Option: C,D
Explanation:
Sucrose or sugar is a polar compound which can break the H-bond present in water due to this reason sugar can dissolve in water . 
Blood is a colloid or suspension composing red blood cells floating in a liquid plasma.If we add it to water, the plasma disperses in the water, becoming more dilute.
Oil and ghee are non-polar in nature as a result they can't interact with a polar solvent like water hence they are insoluble in water.

Which of the following is denser than water?

evs experiments with water water and its types hard and soft water what floats - what sinks

  1. Wooden plank

  2. Buttons

  3. Nails

  4. Paper

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Correct Option: B,C
Explanation:
The density of nail (as of iron) is much larger than the water. So it sinks easily.
The button is more dense than the water and sinks in water.

Chemically calgon is:

evs experiments with water water and its types hard and soft water what floats - what sinks

  1. sodium aluminosilicate

  2. sodium sulphate

  3. sodium hexa meta phosphate

  4. alkyl sulphonic acid

Show answer
Correct Option: C
Explanation:

Calgon is a trade name of a complex salt, sodium hexametaphosphate $(NaPO _3) _6$.