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64. Osmium has the capacity to expands its octet by utilising all the electrons from its 6s and 5d orbitals this results it to attain an oxidation state of +8.

Both the statements assertion and reason are correct but reason is not the correct explanation of assertion. The correct option is B.

63. Cu lies below hydrogen in electrochemical series and has positive electrode potential. hence cannot liberate hydrogen from acids. 

Both the statements assertion and reason are correct and reason is the correct explanation of assertion. 

62. Actinoids are more reactive than lanthanoids as they involve their 5d-orbital in the bond formation process while due to effectively shielded and greater nuclear charge 4f-orbitals are not available for bonding. Thus, lanthanoids comparatively form less complexes than actinoids. 

Assertion is not true but reason is true.

61. Although Zr and Hf lie in same group but As an effect of lanthanide contraction, zirconium and hafnium have similar radius of 160pm and 159 pm respectively. Due to this similarity in their size, they show similar physical and chemical properties. As a result, Zr and Hf are difficult to separate. Both the statements assertion and reason are correct but reason is not the correct explanation of assertion. 

Students can visit the official website of Mohamed Sathak College of Arts and Science to access the detailed BSc fee structure. The total fee includes not just tuition, but also university charges, examination fees, and administrative costs. Reviewing the fee breakdown online ensures clarity for prospective students before they proceed with the application or admission process.

Yes, the college supports talented athletes by offering admissions through the Sports quota. Additionally, scholarships are available for students who have represented at the District, State, or National level in sports. This initiative aims to encourage sports participation while supporting students academically, helping them balance both athletic achievements and their pursuit of higher education.

The eligibility for BSc specialisations in MSCAS depends on the course. For Biochemistry, subjects like Chemistry and Biology are required. Biotechnology requires a science background with Biology/Botany/Zoology. Microbiology applicants must have completed Class 12 with Biology-related subjects, as per the University of Madras norms. Students should verify specific criteria before applying to ensure they meet the required academic qualifications.

60. All halogens combine with copper to form copper halides except iodine. The reason behind this is that Cu²⁺  oxidises iodide (-1)  to iodine (0). Therefore, Cu²⁺ iodide does not exist .Both the statements assertion and reason are correct and reason is the correct explanation of assertion. 

BSc programme at Mohamed Sathak College of Arts and Science spans three years and is divided into six semesters. During this period, students engage in theoretical and practical learning in their chosen specialisation. The structured semester system allows for progressive learning and assessment, ensuring students gain a strong foundation in their respective fields.

59.  (B) and (C) 

Electronic configuration of cerium:

Ce  -  4f¹ 5d¹ 6s²

Ce⁴⁺?  4f⁰ 5d⁰ 6s⁰ 

Lead has the tendency to lose its four outer electrons to attain Noble gas configuration and this removal of electrons corresponds to the f? configuration and cause it to be stable in +4 oxidation state

58.  (B) and (C) 

A compound act as oxidising agent when it's central atom is reduced to its lower oxidation state. This occurs only when the lower oxidation state of metal is more stable than the higher oxidation states. 

In metal WO₃ and CrO₄^2- , both W and Cr are stable in their higher oxidation state and won't get reduced to their lower oxidation state. Therefore, will not act as oxidising agents. 

While the college does not publicly release exact cutoff ranks or marks, here's what the criteria suggest:

Admission lists are prepared from the best four subjects in Class 12, excluding environmental studies .

Given that Honours seats are limited (approved intake ranges from 82–200 across Hons streams) , the actual cutoff is likely well above the minimum eligibility—probably in the 55–60%+ range, particularly for English honour

s.

57.  (A) and (B) 

Cr and Co  form tri halide compounds.

55.  (B) and (C) 

Ce (Z = 57)  =  [Xe] 4f⁵ 5d⁰ 6s² , O.S.  =   + 3, + 4

Eu (Z = 63)  =  [Xe] 4f⁷ 5d⁰ 6s², O.S.  =   + 2, + 3

Yb (Z = 70)  =  [Xe] 4f¹⁴ 5d⁰ 6s², O.S.  =   + 2, + 3

Ho (Z = 67)  =  [Xe] 4f¹¹ 5d⁰ 6s², O.S.  =   + 3 

54.  (A) and (B)

Electronic configuration:

92U -  5f³ 6d¹ 7s²

93Np -  5f⁴ 6d¹ 7s² 

53.  (B) & (D) 

Actinides show a variety of oxidation states like +3, +5, +6 and +7. 

From the given option, plutonium and neptunium show all oxidation states up to +7

52.  (B) and (C) 

For the heavier metals of d-block, higher oxidation state is more favourably stable than the lower oxidation state. For example: Mo (VI) and W (VI) are more stable than Cr (VI). For lighter d-block elements like chromium, +3 oxidation state is more stable. So, Cr (VI) in dichromate act as a strong oxidising agent by reducing itself from +6 to +3 oxidation states While Mo (VI) and W (VI) does not.