Polar Molecules

Q.

Balance the following chemical equation

Calcium hydroxide + carbon dioxide -calcium carbonate + water

Q.

Why ammonium ion contains a positive charge when hydrogen accepts lone pair of electrons from ammonia and forms coordinate bond .

Q. Name two gases which can be used in the study of the fountain experiment. State the common property demonstrated by the fountain experiment.

Q.

What happens when carbon dioxide dissolves in water what is the use of this element

Q.

The intermolecular forces of alcohol are weaker than in water

1. True
2. False

Q.

Explain circumstances leading to acid rain. How does acid rain affect us?

Q.

Hydrogen chloride solution in water turns blue litmus red, and conducts electricity, while in toluene does not. Explain why.

1. Solution of hydrogen chloride in toluene is metallic in nature.
2. Solution of hydrogen chloride in toluene is covalent in nature.
3. Solution of hydrogen chloride in toluene is ionic in nature.
4. None of these

Q. What happens when NaCl is added to water?

1. NaCl dissociates
2. NaCl does not dissociate
3. NaCl gets mixed in water
4. None of these

Q. Why HCL and HNO₃ cannot dissolve Gold and Platinum alone but their mixture, Aqua-Regia can?

Q.

The O-H bond in water is polarized due to __.

1. Low electronegativity difference between oxygen and hydrogen atom.

2. Large difference in the electronegativity values of the oxygen and hydrogen atom.

3. No difference in the electronegativity values of the oxygen and hydrogen atom.

4. Small size of oxygen.

Q.

Which atom has higher electronegativity in the HCl molecule?

1. Chlorine atom

2. Hydrogen atom

3. Both are equally electronegative.

4. Both are equally electropositive.

Q.

When the stopper of a bottle full of hydrogen chloride liquid is opened, fumes can be seen coming out. Why does this happen?

1. Hydrogen chloride is a noble gas.

2. HCl is a weak acid.

3. There is an immediate reaction between hydrogen chloride gas and water vapour in the air.

4. It reacts with the bottle to release fumes.

Q.

Do acids dissociate or ionize?

Q.

BALANCE THIS EQUATION WITH STEPS:

HNO₃+Ca(OH)₂>>>Ca(NO₃)₂+H₂O

Q.

Write the balanced chemical equation for the following reaction.

Lead nitrate solution is added to sodium chloride solution.

1. 

2. 

3. 

4. 

Q.

Explain the following briefly:
(a) Sodium chloride dissolves in water but carbon tetrachloride is insoluble in water.
(b) Helium does not form He₂ molecule.
(c) Pure water does not conduct electricity, but on adding sodium chloride to it, it starts conducting electricity.
(d) Cl₂ is a non-polar molecule, while HCl is a polar molecule.
(e) Metals are electropositive.

Q.

The formula of chloric acid is HClO₃

1. True
2. False

Q. What are isoelectronic species?

Q. Why Aqua-Regia is a mixture of only HCL and HNO₃ and not of other acids?

Q. what is the bond order of CH4 molecule?

Q. On adding a drop of barium chloride solution to an aqueous solution of sodium sulphite, white precipitate is obtained. On adding dilute hydrochloric acid to the reaction mixture, white precipitate disappears. Why?

Q.

Balance the following equations

a)Pb(NO₃)₂ gives PbO +NO₂+O₂

b)NH₃+CuO gives Cu+N₂+H₂O

c)NaOH+H₂SO₄ gives Na₂SO₄ +H₂O

d)Al₄C₃+H₂O gives CH₄+Al(OH)₃

Q.

A colourless and odourless gas is liberated when hydrochloric acid is added to a solution of washing soda. The name of the gas is:

1. Sulphur dioxide

2. Nitrogen dioxide

3. Sulphur trioxide

4. Carbon dioxide

Q.

Name the acid used for the preparation of hydrogen chloride gas in the laboratory. Why is this particular acid preferred to other acids?

Q.

Balance the chemical equation Na+H₂O= NaOH+H₂

Q.

When you heat a magnesium ribbon on a burner it burns with the blinding white light and some Residue is left after burning. The residue appears to be like

1. lamp black

2. Charcoal Ash

3. powdered salt

4. solid mass

Q.

how to balance chemical reaction of sodium+ water---->sodium hydroxide+hydrogen

please explain in brief

Q.

Which one of the following reaction is not balanced?

1. 2KI + H₂O₂ → 2KOH + I₂

2. CaCO₃ → CaO + CO₂

3. Mg + 2HCl → MgCl₂ + H₂

4. 2Fe + 3H₂O → Fe₂O₃ + H₂

Q.

What is wrong with the following equation

Mg+O=MgO

Identify the mistake and balance the equation

Q. A student takes NA2CO3 powder in a test tube and pour some drops ofacetic acid over it .write any two observations that will see.