Sample Paper-II (Unsolved) Subject : Chemistry

Time: 3 Hrs. Class: IX M.M.: 70

General Instructions:

1. All questions are compulsory.

Marks for questions are indicated against each.

1. Question no. 1-8 are very short answer questions carrying 1 march each.
2. Questions no. 9-18 are short answer questions carrying 2 marks each.
3. Question no. 19-27 are also short answer question carrying 3 marks each.
4. Question no. 28-30 are long answer questions carrying 5 marks each.
5. Answer should be brief and to the point.

1. Write the correct set of four quantum numbers for the valence electron of potassium <math>(Z = 19)</math>.
2. Write the IUPAC name and symbol for the element with atomic number 199.
3. What property of molecules of real gases is indicated by van der Walls constant 'a'?
4. When 430J of work was done on a system, it lost 120J of energy as heat. Calculate the value of internal energy change (<math>\Delta U</math>) for this process.

1. Write K, is terms of K, for the following chemical reaction: <math>2SO_{s}(g) + O_{s}(g) \rightleftharpoons 2SO_{s}(g)</math>
2. Given an example of disproportionation reaction.
3. Name the isotope of hydrogen which contains equal number of protons and neutrons.
4. Write IUPAC name of the following organic compund: <math>CH_1 - C(CH_1), -CH = CH,</math>

1. A sample of drinking water was found to be severely contraminated with chloroform (CHCl₃), supposed to be carcinogenic in nature. The level of contamination was 15ppm (by mass).
2. Express this in percent by mass.
3. Determine the molality of chloroform in the water sample. [Given molar mass of CHCl₃ = 118.5g-mol^-1]

2 135

An electron has a speed of 40ms^-1 accurate upto 99.99%. What is the uncertainty in locating its position? [Given <math>m_e = 9.11 \times 10^{-3}1</math> kg] 2 2

Give correct reason for the following:

1. BF₃ has a zero dipole moment although the B–F bonds are plar.

All carbon to oxygen bonds in CO₁² are equivalent.

1. Balance the following redox reaction by ion electron method (in basic

medium): 2

<math>MnO_{s}^{-}(aq) + \Gamma(aq) \rightarrow MnO_{s}(s) + I_{s}(s)</math>

1. Complete the following reactions: 2
2. PbS (s)+H₂O₂ (aq) →
3. Ca(HCO₃)₂+Ca(OH)₂ →

OR Account for the following:

1. Soft water lathers with soap but not hard water.

Temporary hardness of water can be removed by boiling.

1. Mention the type of hybridisation of each carbon in the 2
2. Draw the structure of 2-methylpropan-2-ol.

In sulphur estimation, 0.157g of an organic compound gave 0.4813g 2

of barium sulphate. What is the percentage of sulphur in the compound?

1. Write the structures of products (A and B) of the following reactions: 2

compound CH3 - CN.

1. <math>HC \equiv CH \xrightarrow{Na} A \xrightarrow{CH_3Br} B</math>
2. <math>BrH_1C - CH_2Br \xrightarrow{Alcohol} A \xrightarrow{NaNH_2} B</math>
3. Arrange the following in order of property mentioned against each: 2
4. BeCl₂, MgCl₂, CaCl₂, BaCl₂ [Increasing ionic character]
5. Mg(OH)₂, Ca(OH)₃, Ba(OH)₃, Sr(OH), [Increasing solubility in water]

Give reasons for the following:

1. The enthalpy of neutralisation is always constant i.e., 57.1 kJ/mol when a strong acid neutralises a strong base.

Neither q nor W is a state function but q + W is a state function. 136