chemical bonding and acid base

CHEMICAL BONDING & dr ACIDS, BASES SALTS

1.      From the following list of substances choose the one substance in each case which matches the description (i) to (vi) given below:

Ammonium nitrate, calcium hydrogen carbonate, copper carbonate, lead carbonate, lead nitrate, potassium nitrate, sodium carbonate, sodium hydrogen carbonate, zinc carbonate.

                                i.            A hydrogen carbonate which exists in the solid state.

                              ii.            A carbonate not decomposed by heat.

                            iii.            A nitrate which gives off only oxygen when heated.

                            iv.            A nitrate which on heating decomposes into dinitrogen oxide and steam.

                              v.            A nitrate which gives off oxygen and nitrogen dioxide when heated.

2.      State what you observe when :

1. Neutral llitmus solution is added to an alkaline solution.

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2. Lead nitrate solution and sodium chloride solution are mixed.

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3.      Mention the terms defined by the following sentences:

1. A soluble base
2. An acidic solution in which there is only partial ionization of the solute molecules
3. The insoluble solid formed when two solutions are mixed together

4.      Write the equations for the laboratory preparation of:

1. Sodium sulphate using dilute sulphuric acid

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2. Lead sulphate using sulphuric acid.

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5.      If HS is a weak acid, what particles will be present in its dilute solution apart from those of water?

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6.      Write balanced equations for the following reactions:

1. Lead sulphate from lead nitrate solution and dilute sulphuric acid.

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2. Copper sulphate from copper and concentrated sulphuric acid.

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3. Lead chloride from lead nitrate solution and sodium chloride solution.

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4. Ammonium sulphate from ammonia and dilute sulphuric acid.

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5. Sodium chloride from sodium carbonate solution and dilute hydrochloric acid.

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7.      Name the charged particles which attract one another to form electrovalent compounds.

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8.      Electrons are getting added to an element Y:

1. Is Y getting oxidized or reduced?
2. What charge will Y have after the addition of electrons?
3. Which electrode will Y migrate to during the process of electrolysis?

9.      Draw an electron dot diagram of a hydronium ion and label the lone pair of electrons.

10.  In the formation of magnesium chloride name the substance that is oxidized and the substance that is reduced.

11.  State two differences you would expect to find between the properties of carbon tetrachloride and sodium chloride.

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12.  Give the reason why ionic compounds have high melting point and boiling  point.

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13.  State which of the following are oxidized or reduced:

1. N  -à N^3-
2. Cl^- àCl₂
3. Cu  à Cu²⁺
4. Cr  à Cr³⁺

14.  Element X is a metal with a valency 2.  Element Y is a non metal with a valency 3.

1. Write equations to show how X and Y form ions.

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2. If Y is a diatomic gas, write the equation for the direct combination of X and Y to form a compound.

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15.  Explain the following briefly:

1. Helium does not form He₂  molecule.

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2. Metals are electropositive.

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