CBSE Important Questions

Chemistry Class X

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  1. Draw the structure of ethene molecule (C2H4)
  2. The position of three elements A, B and C in the periodic table are shown below :
    Group 16 Group 17
    - -
    - A
    - -
    B C
    1. State whether A is a metal or non - metal.
    2. State whether C is more reactive or less reactive than A.
    3. Will C be larger or smaller in size than B ?
    4. Which type of ion, cation or anion, will be formed by element A ?
  3. What are soaps ?  Explain the mechanism of the cleansing action of soaps.
  4. a. Atomic number is considered to be a more appropriate parameter than atomic mass for classification of elements in a periodic table. Why ?
    b. How does atomic size of elements vary on moving from :
    1. left to right in a period ?
    2. top to bottom in a group ?
  5. Give reasons for your answers.
    1. The atomic number has been chosen as the basis for classifying elements. Why ?
    2. By considering their positions in the Periodic Table, which one of the following elements would you expect to have maximum metallic characteristic ?
      Na, Mg, Al.
  6. A part of the Periodic Table has been shown below -
    Group l ll XVI XVII XVIII
    Period 1          
    2   B D C  
    3       E  

    On the basis of above table answer the following questions -
    1. Which element will form cation ?
    2. Which element will have the smallest atomic size ?
    3. Which element will have chemical properties similar to Magnesium (atomic number 12) ?
    4. Write the common name of the group to which C and E belong.
    1. Which of the following compounds will undergo addition reaction ?
      C2H6, C3H8, C3H6, C2H2, and CH4
    2. What is hydrogenation ?  State its industrial application.
    1. Name an element you would expect to show chemical reactions similar to sodium. State the reason in support of your answer.
    2. Write electronic configuration of the element belonging to 3rd period and 13th group of the periodic table. Predict whether it is a metal or a non - metal. Give reason.
  9. Write the name and structure of an aldehyde with 4 carbon atoms.
    1. State the Modern Periodic Law.
    2. Name the element which has twice as many electrons in its second shell as in its first shell. Write its electronic configuration also.
    1. Why do all the elements of the same group have similar chemical properties ?
    2. Why do all the elements of the same period have different properties ?
    1. An organic compound A is widely used as a preservative in pickles and has a molecular formula C2H4O2 . This compound reacts with ethanol in the presence of a mineral acid to form a sweet smelling compound B.
      1. Identify the compound A.
      2. Which gas is produced when A reacts with sodium carbonate ? Write the balanced chemical equation for the reaction involved.
    2. Write the names of
      1. CH3CH2Br
      2. CH3-CH=CH2
    1. How and why does the size of an atom vary on moving  from left to right in a period ?
    2. Why does the chemical reactivity of metals increase on moving down a group ?
  14. Name the functional group present in propanone, CH3COCH3.
  15. the elements of the third period of the periodic table are given below:
    Na Mg Al Si P S C1 Ar
    Which atom is bigger Na or Mg ? Why ?
    Identify the most (i) metallic and (ii) non-metallic element
  16. This question refers to the elements of the periodic table with atomic numbers 3 to 18
    1. Which of them are noble gases ?
    2. Which of them are halogens ?
    3. Which of them are alkali metals ?
    4. What is the electronic configuration of an element with atomic number 10 ?
    1. Draw the structures for following compounds
      (i) ethanoic acid,
      (ii) butanone, C2 H5 CO CH3.
    2. Conversion of ethanol to ethanoic acid is considered an oxidation reaction. Why?

    1. Give a chemical test to distinguish between saturated and unsaturated hydrocarbons.
    2. Name the products formed when ethanol burns in air.
    3. Why is the reaction between methane and chlorine considered a substitution reaction ?

Submitted By Mr. Atul Kumar Gaur
Email Id : atulgaur@gmail.com
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