HCS Mains 2021 Chemistry Question Paper Page 1-2

Haryana Government Jobs Administrative / Civil Services 2021

  • Year 2021
  • Conducted By HCS (Ex.Br.) & Other Allied Services
  • Maximum Marks 200
  • Duration 3 Hours
  • Languages English & Hindi

Exam Details

Detail Information
Examination Chemistry
Year 2021
Conducting Body HCS (Ex.Br.) & Other Allied Services
Paper Chemistry
Subject Chemistry
Duration 3 Hours
Maximum Marks 200

Page 1 provides the exam header, conducting body, paper code, marks, duration, languages, and general instruction context for the Haryana HCS Mains 2021 Chemistry paper. Page 2 contains repaired descriptive questions: 1 with subparts (a)–(e) covering effective nuclear charge in Germanium, CN molecular orbital diagram and bond order, Bragg's law, CST in partially miscible liquids, and CO bond length; and 2 with subparts (a) and (b) addressing a surface energy calculation from a droplet dispersed into microglobules and the Nernst heat theorem. The OCR repair ensures proper separation of questions and bilingual stems where applicable. The content focuses on concepts in physical and inorganic chemistry, requiring both calculations and explanations.

Major Topics Covered

  • Chemistry
  • Physical Chemistry
  • Inorganic Chemistry
  • Molecular Orbital Theory
  • Bragg's Law
  • Nernst Theorem
  • Critical Solution Temperature
  • Bond Order
  • Cyanide Ion
  • CO Molecule
  • CO+ Ion
  • Germanium Electronic Structure
  • Effective Nuclear Charge
  • X-ray Diffraction
  • Thermodynamics
  • Phase Equilibria
  • Binary Liquid Mixtures
  • Molecular Orbitals
  • Surface Energy
  • Microscopy and Microspheres

Why This Paper is Important

  • Useful for Chemistry preparation
  • Helps understand the latest exam pattern
  • Useful for practice and self-assessment
  • Covers frequently asked General Studies topics
  • Helpful for analysing question trends

Related Resources

Instructions

  • 2021 CHEMISTRY l. Answer the following रसायन–शास्त्र में मिमलेला पश्च के उत्तर है (a) Calculate effective nuclear charge felt by 4s, 4p and 3d electrons in ISE OF SHIRO J | Maximum Marks: 200 Time: 3 hours ] समय : 3 घंटे | अप किामार प्राप्त प्रदर्श काम का कोइकांड b.c. क्या अक्षेट के बाद (SE स्वीमत्त प्राप्त | अधिकतम अंक : 200 Instructions (निर्देश): (b) Draw the molecular orbital diagram of cyanide This paper is divided into two Sections, Section-A and Section-B. (i) itm SPS he consider you ये प्रश्नपत्र दो खंडों में विभाजित है, खंड-A और खंड-B I HERD SEEK SID H HUIS SEEMB Each Section contains eight questions. (ii) ne Derive and ta प्रत्येक खंड में आठ प्रश्न हैं।
  • शिक्षांश कर जब होकाल कि (wel aggent) प्रकार क्रियाई tel Wisst is CST? What A candidate has to attempt twelve questions. (iii) woda abiunil inuquu ms ii sansdo एक परीक्षार्थी को बारह प्रश्नों का उत्तर लिखना है। CST क्या है? चो कान-सो प्राते हैं, जिसके Question Nos. 1 and 9 are compulsory and out of the remaining, any (iv) ten are to be attempted choosing five from each Section. प्रश्न संख्या 1 और 9 अनिवार्य हैं और शेष प्रश्नों में से किन्हीं दस का उत्तर लिखना है, प्रत्येक खंड से पाँच–पाँच प्रश्नों को हल करना है। the discot bood because admyliterati CO अर्थ का बाँन्ड लवार्ड 1-128 Å है चर्चाक CO" में गया 15 Å है।
  • परमाज्यक कशक रिस्क्रांड की Question Nos. 1 and 9 consist of five parts each. Each part will be of (v) 6 marks. Word limit will be 150 (in relevant subjects only). प्रश्न संख्या 1 और 9 के पाँच-पाँच भाग हैं।
  • प्रत्येक भाग के लिए 6 अंक निर्धारित हैं।
  • शब्द संख्या 150 तक सीमित है (मात्र सम्बद्ध विषयों में)। \sim 0.04 e बजत बात एक गोलाका।
  • यद का 902 em निक्स दाते 1500 सक्स प्लोक्यों में बिछा दिया (vi) Remaining questions will be of 14 marks each. The sound is the शेष प्रश्न 14 अंकों के प्रति प्रश्न होंगे।¤stosett that share of faste all page नस्टें (Nernst) के ताप प्रपेद्य को व्यक्त करते हुए इसकी व्याख्या करें। A \in \mathbb{R}

Questions (page 2)

Q1.

(a) SECTION खड़ 6 × 5 = 30 1. Answer the following questions: निम्नलिखित प्रश्नों के उत्तर दें: Calculate effective nuclear charge felt by 4s, 4p and 3d electrons in 008 : al Germanium (Atomic No. 32). 00\%: काल्जर्मेनियम (परमाणु क्रमांक 32) में 4s, 4p एवं 3d इलेक्ट्रॉनों द्वारा अनुभव किए गए प्रभावी परमाणुवीय चार्ज पता करें। Instruct

(b) Draw the molecular orbital diagram of cyanide ion (CN), labelling each orbital clearly. Calculate the bond order in cyanide ion. हर कक्षक को स्पष्ट रूप से लेबेल करते हुए सायनाइड आयन के परमाण्विक कक्षक का आरेख बनाएँ। सायनइड आयन में बाँड आर्डर (बंधन क्रम) की गणना करें। anp drigle arried do nothe

(c) Derive and explain Bragg's law. ब्रैग का नियम (Bragg’s law) को व्युत्पत्रि करें एवं समझाएँ। संस्कृत को साल के साथ स

(d) What is CST? What are the conditions under which two partially miscible liquids show
(i) upper CST and
(ii) lower CST. How will the lower CST change if an impurity soluble in both the liquids is added to the system? CST क्या है? वो कौन-सी शर्तें हैं, जिसके तहत दो आंशिक विलयशील द्रव दर्शाते हैं— gan
(i) 340 CST at a complete the problem in the set of the September of ten ard to be attempted choosing five from each Serge TRO
(ii)

(e) The bond length in CO molecule is 1.128 Å while in CO + , it is 1.115 Å. Justify the reduced bond length with the help of molecular orbital theory. CO अणु का बॉन्ड लंबाई 1·128 Å है जबकि CO^+ में 1·115 Å है। परमाण्विक कक्षक सिद्धांत की सहायता से, कम हुए बॉन्ड लंबाई का औचित्य सिद्ध करें। (a) A spherical drop of a liquid weighing 0.04 g is dispersed into 1500

Q1.

(a) SECTION खड़ 6 × 5 = 30 1. Answer the following questions: निम्नलिखित प्रश्नों के उत्तर दें: Calculate effective nuclear charge felt by 4s, 4p and 3d electrons in 008 : al Germanium (Atomic No. 32). 00\%: काल्जर्मेनियम (परमाणु क्रमांक 32) में 4s, 4p एवं 3d इलेक्ट्रॉनों द्वारा अनुभव किए गए प्रभावी परमाणुवीय चार्ज पता करें। Instruct

(b) Draw the molecular orbital diagram of cyanide ion (CN), labelling each orbital clearly. Calculate the bond order in cyanide ion. हर कक्षक को स्पष्ट रूप से लेबेल करते हुए सायनाइड आयन के परमाण्विक कक्षक का आरेख बनाएँ। सायनइड आयन में बाँड आर्डर (बंधन क्रम) की गणना करें। anp drigle arried do nothe

(c) Derive and explain Bragg's law. ब्रैग का नियम (Bragg’s law) को व्युत्पत्रि करें एवं समझाएँ। संस्कृत को साल के साथ स

(d) What is CST? What are the conditions under which two partially miscible liquids show
(i) upper CST and
(ii) lower CST. How will the lower CST change if an impurity soluble in both the liquids is added to the system? CST क्या है? वो कौन-सी शर्तें हैं, जिसके तहत दो आंशिक विलयशील द्रव दर्शाते हैं— gan
(i) 340 CST at a complete the problem in the set of the September of ten ard to be attempted choosing five from each Serge TRO
(ii)

(e) The bond length in CO molecule is 1.128 Å while in CO + , it is 1.115 Å. Justify the reduced bond length with the help of molecular orbital theory. CO अणु का बॉन्ड लंबाई 1·128 Å है जबकि CO^+ में 1·115 Å है। परमाण्विक कक्षक सिद्धांत की सहायता से, कम हुए बॉन्ड लंबाई का औचित्य सिद्ध करें। (a) A spherical drop of a liquid weighing 0.04 g is dispersed into 1500

Q2. microglobules of radius 0.02 cm. Find the resultant increase in surface 6 energy. 0·04 g वजन वाले एक गोलाकार बूंद को 0·02 cm त्रिज्या वाले 1500 सूक्ष्म ग्लोब्यूलों में बिखेर दिया जाता है। सतह ऊर्जा में परिणामी वृद्धि निकालें। To ed Iliw enotheoryp grimismost 2 (b) State and explain Nernst heat theorem. The finite of FOR PR नर्स्ट (Nernst) के ताप प्रमेय को व्यक्त करते हुए इसकी व्याख्या करें। ACE grisimad: Chemistry/29A

Q2. microglobules of radius 0.02 cm. Find the resultant increase in surface 6 energy. 0·04 g वजन वाले एक गोलाकार बूंद को 0·02 cm त्रिज्या वाले 1500 सूक्ष्म ग्लोब्यूलों में बिखेर दिया जाता है। सतह ऊर्जा में परिणामी वृद्धि निकालें। To ed Iliw enotheoryp grimismost 2 (b) State and explain Nernst heat theorem. The finite of FOR PR नर्स्ट (Nernst) के ताप प्रमेय को व्यक्त करते हुए इसकी व्याख्या करें। ACE grisimad: Chemistry/29A

Q3. 1. c) Derive and explain Bragg's law.

Q4. 1. d) What is CST? What are the conditions under which two partially miscible liquids show
(i) upper CST and
(ii) lower CST? How will the lower CST change if an impurity soluble in both the liquids is added to the system?

Q5. 1. e) The bond length in CO molecule is 1.128 Å while in CO+ is 1.115 Å. Justify the reduced bond length with the help of molecular orbital theory.

Q6. 2. a) A spherical drop of a liquid weighing 0.04 g is dispersed into 1500 microglobules of radius 0.02 cm. Find the resultant increase in surface energy.

Q7. 2. b) State and explain Nernst heat theorem.

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Frequently asked questions

What is CST?

CST stands for Critical Solution Temperature, the temperature at which two partially miscible liquids become completely miscible or immiscible depending on the system.

Under what conditions do two partially miscible liquids show upper CST and lower CST?

Upper CST occurs when solubility increases with temperature leading to miscibility at higher temperatures; lower CST occurs when solubility decreases with temperature leading to miscibility at lower temperatures.

How does adding an impurity soluble in both liquids affect CST?

The addition of a solute soluble in both liquids generally shifts the CST, often affecting the temperature at which phase separation occurs (lower CST behavior can be modified).

What is Bragg's law?

Bragg's law is nλ = 2d sin θ, relating the wavelength, interplanar spacing, and angle of incidence for constructive interference in X-ray diffraction.

What is the bond order in CN (cyanide ion)?

Bond order is calculated from the MO diagram of CN; the exact value depends on the filled molecular orbitals and electrons in CN.

Explain the concept of effective nuclear charge (Z_eff).

Z_eff is the net positive charge experienced by a valence electron, accounting for shielding by inner electrons and the actual nuclear charge.

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