CLASS X:IMPORTANT QUESTIONS: CHEMISTRY

SCIENCE QUESTION BANK :

CHEMISTRY

1. Write the two succeeding members of the following homologous series : C₂H₆, C₃H₈.
2. How does the atomic radii of elements change in periodic table :
   (a) down the group
   (b) across the period from left to right
3. State modern periodic table law. What is the number of total periods and groups in periodic table.
4. Explain why it is difficult to wash clothes with soap when water is hard. How do detergents help in overcoming this problem ?
5. Part of the periodic table is given below where atomic numbers of elements are given in the parenthesis.
   Li (3) Be (4) Na (11) Mg (12)
   K (19) Ca (20) Rb (37) Sr (38)
   (I) Give the electronic configuration of K.
   (ii) Predict the number of valance electrons in the atom of Ca.
   (iii) What is the number of shells in the atom of Na ?
   (iv) Arrange Be, Mg, Ca, Sr in the increasing order of the size of their respective atoms.
   (v) Predict whether Rb is a metal or non metal.
   (vi) Out of Na, Li, Be and Mg which one has biggest atom in size ?
6. (i) Explain the two characteristic features that are seen only in carbon and not in any other
   element, to form a large number of compounds.
   (ii) Write the names of the next homologue of CH₃ CH₂ OH and HCOOH.
7. A compound X is used in cough syrups and many tonics. It is also soluble in water in all proportions.
   (i) Name the compound X. Write its chemical formula.
   (ii) Which gas is evolved when the compound X reacts with sodium ? How will you test the presence of this gas ? Write the chemical equation involved in reaction of X with sodium.
8. Mention any two trends exhibited by elements when we go from left to right across the period of periodic table.
9. “Elements in Periodic Table show periodicity of properties” List any four such properties.
10. Write the name of the next homologue of CH₃OH and HCOOH.
11. How does boiling point and melting point of hydrocarbons change with increase in molecular mass ?
12. (a) Define homologous series of organic compounds. Mention any two characteristics of homologous series. (b) Describe a chemical test to distinguish between ethanol and Ethanoic acid. (c) Identify functional group in Pentanone.

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