# Solved papers for 10th Class Science Solved Paper - Science-2017 Delhi Set-II

### done Solved Paper - Science-2017 Delhi Set-II

• question_answer1) Write the molecular formula of first two members of homologous series having functional group - Br

• question_answer2) How does Planaria reproduce? Is this method sexual or asexual?

• question_answer3) Why is forest considered a natural ecosystem?

• question_answer4) Explain how would the involvement of local people be useful for successful management of forests.

 Complete the following chemical equations: (i) $\mathbf{C}{{\mathbf{H}}_{\mathbf{3}}}\mathbf{COOH+N}{{\mathbf{a}}_{\mathbf{2}}}\mathbf{C}{{\mathbf{O}}_{\mathbf{3}}}\xrightarrow{{}}$ (ii) $\mathbf{C}{{\mathbf{H}}_{\mathbf{4}}}\mathbf{+}{{\mathbf{O}}_{\mathbf{2}}}\xrightarrow[{}]{{}}$ (iii) $\mathbf{2}{{\mathbf{C}}_{\mathbf{2}}}{{\mathbf{H}}_{\mathbf{5}}}\mathbf{OH+Na}\xrightarrow[{}]{{}}$

 Two carbon compounds X and Y have the molecular formula ${{\mathbf{C}}_{\mathbf{3}}}{{\mathbf{H}}_{\mathbf{6}}}$ and ${{\mathbf{C}}_{\mathbf{4}}}{{\mathbf{H}}_{\mathbf{10}}}$ respectively. Which one of the two is most likely to show addition reaction? Justify your answer. Also give the chemical equation to explain the process of addition reaction in this case.

• question_answer7) Mention the total number of chromosomes along with the sex chromosomes that are present in a human female and a human male. Explain how in sexually producing organisms the number of chromosomes in the progeny remains the same as that of the parents.

• question_answer8) "Natural selection and speciation leads to evolution". Justify this statement.

• question_answer9) A 3 cm tall object is placed 18 cm in front of a concave mirror of focal length 12 cm. At what distance from the mirror should a screen be placed to see a sharp image of the object on the screen. Also calculate the height of the image formed.