HSC Chemistry 1st Paper Model Question-3
Class - XI
Subject : Chemistry
Time : 3 hrs. Marks. 75
Section A : Descriptive question
1. a) Write down the basic postulates of kinetic theory of gases. 5
b) Deduce PV=nRT equation for ideal gases. 5
c) At 270c specific mass of gas along with a solid substance has the total volume 100L. When its temperature is increased to 540C, its presssure is doubled and its volume is 59.3 L. Find the volume of the solid substance. 5
Or,
a) State the modern periodic law. Discuss the position of Hydrogen in the periodic table. 2+3
b) Write down the Dalton's law of partiaal pressure Deduce the relation between partial pressure of a gas and mole fraction. 2+3
c) Define Normality ? From 250 cm3 of 0.5 M NaOH solution what vvolume of deci-molar Na2CO3 solution would be made ? 2+3
HSC Chemistry 1st Paper Model Question
2. a) Write down the fundamental postulates of Bohr's atom model. 5
b) Explain ionic character of covalent bond and covalent character of ionic bond. 4
c) What is ionic bond ? The percentage of C & H in a compound is 54.54% and 9.09%. respectively.The rest of the compound is O. If its vapour density is 44, then determine the molecular formula. 1+5
Or,
a) Explain Ostwald's dilution law. Deduce Henderson's equation for calculating the PH of a basic buffer so1n. 4
b) What is La-Chatelier's principle ? Explain the effect of Temperature and pressure on chemical equilibrium according to this principle. 2+3+3
c) To prepare a buffer soln of 4.75 PH, how many moles of sodium propionate is to be added with 0.02 mol propanoic acid in a 1.0 dm3 ? 3
3. a) What are sigma and pi bonds ? Write down some differences between them. 2+3+3
b) What is electronegativity ? Why does the electronegativity increases as the atomic number increases from left to right of the elements of the same period of a periodic table. 2+3
c) Calculate the oxxidation number of Fe and Cu in [Fe (CN)6]3- and [Cu(NH3)4]2+ respectively.
d) A 15 cm3 solution of 0.3 M KMnO4 mixed with dil H2SO4 can oxidize 25 cm3 of H2O2 Soln. Find the molar concentration of H2O2 in soln. 3
Or,
a) What is nuclear fission and nuclear fusion ? Write down the differences between them. 2+3
b) Write down the electronic configuration of the following ions. 3
Cu2+ (29)
Fe2+ (26)
Mn2+ (25)
c) Write short notes on : 4
i) Pauli's exclusion principle.
ii) RMS velocity.
d) 
+ ? 
+ 
+ 
?+ 
H s Section B : Short type question.
4. a) What is metallic bond ? Explain with example. 3
b) Why is HCl polar ? 2
Or,
a) Describe SP3 hybridization with example. 3
b) NCl5 does not exist but PCl5 exists -Why ? 2
5. a) CO2 is gaseous but SiO2 solid -Why ? 3
b) Which one is more ionic and why? KCl or CaCl2 . 2
Or,
a) Write the causes for the inertness of inert gases. 3
b) Write two differences between Empirical formula and Molecular formula. 2
6. a) What are possible and what are not ? 3d, 2d, 6s 3
b) What is isotope and isobar ? 2
Or,
a) Describe "Diagonal relationship." 3
b) Find out the strength of 10% Na2CO3 in terms of molarity. 2
7. a) What is mole fraction ? 2
b) Balance this reaction : 3
K2Cr2O7 + KI+ H2SO4 Cr2 (SO4)3 + K2SO4 + H2O + 12.Or,
a) What is polarisation ? 2
b) H2O liquid but H2S is gas ? 3
8. a) What is heat of neutralisation ? 2
b) What types of bond are present in the following compounds. 3
i) CH4 ii) Ca Cl2 iii) (H2O)n
Or,
a) Find the position of Sc (21) and K (19) in the periodic table. 2
b) Write down three differences between oxidation number and valency ? 3
9. a) Al f3 is ionic compound, Al Cl3 has covalent character-explain. 3
b) What is hydrogen bond ? 2
Or,
a) At 200c and 740 mm pressure 0.842 gm of a gas has the volume 400 ml. What is its molecular mass ? 3
b) What is oxidising agent ? 2
HSC Chemistry 1st Paper Model Question
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