CBSE Class 11 Chemistry Solved Practice Paper 2017 – 2018: Set III
CBSE Solved Paper for Class 11th Chemistry 2017 – 2018 final exam is available here for download in PDF format. You can download the completely solved paper with the help of download link given at the end of this article.
With the help of these CBSE Chemistry solved paper, students will get an idea about the level of questions which are frequently asked in CBSE school exams.
Most of the questions given in this 11th Chemistry Solved Paper are based on important concepts of NCERT textbooks and previous year papers of different CBSE schools. These questions are very important for coming CBSE Class 11th Chemistry exam 2018. Time duration to solve this paper is 3 hours but students should try to solve this paper in less than 3 hours as this will enhance their writing speed.
Some important questions from class 11 Chemistry solved paper are given below:
Explain why molar enthalpy of vaporisation of acetone is less than that of water.
Due to strong hydrogen bonding in H2O molecules, enthalpy of vaporisation of water is more than that of acetone because there is strong hydrogen bonding in H2O molecules.
Which will undergo nitration more easily and why?
Benzene, m-dinitrobenzene and toluene
‒NO2 group is electron-withdrawing whereas CH3 group is electron-donating while. Therefore, maximum electron density will be in toluene, followed by in benzene and least in m-dinitrobenzene. Therefore, the ease of nitration decreases in the order:
Toluene > Benzene > M-dinitrobenzene
Reaction between H2 and Cl2 is slow but reaction between NaCl and AgNO3 is very fast. Explain
The reaction between H2 and C12 involves breaking of covalent bonds which requires energy. On the other hand, NaC1 & AgNO3 are ionic compounds. In the solution, NaCI gives Na+ and Cl‒ ions and AgNO3 gives Ag+ and NO3‒ ions. The oppositely charged Ag+ and Cl‒ ions combine immediately.
How would you explain the lower atomic radius of Ga as compared to Al?
Due to poor shielding of the valence electrons of Ga by the inner 3d-electrons, the effective nuclear charge of Ga is greater in magnitude than that of Al. As a result, the electrons in gallium experience greater force of attraction by the nucleus than in Al and hence atomic size of Ga (135 pm) is slightly less than that of Al (143 pm).
Question: Write some differences between the terms electron gain enthalpy & electronegativity?
Electron gain enthalpy refers to the tendency of an isolated gaseous atom to accept an additional electron to form a gaseous negative ion, electronegativity refers to the tendency of the atom of an element to attract the shared pair of electrons towards it in a covalent bond.
Other questions and solutions are availble in PDF.