-
Engineering and Architecture
Exams
Colleges
Predictors
Resources
-
Computer Application and IT
Quick Links
Colleges
-
Pharmacy
Colleges
Resources
-
Hospitality and Tourism
Colleges
Resources
Diploma Colleges
-
Competition
Other Exams
Resources
-
School
Exams
Ranking
Products & Resources
-
Study Abroad
Top Countries
Student Visas
-
Arts, Commerce & Sciences
Exams
Colleges
Upcoming Events
Resources
-
Management and Business Administration
Exams
Colleges & Courses
Predictors
-
Learn
Online Courses
Engineering Preparation
Medical Preparation
-
Online Courses and Certifications
Top Streams
Specializations
- Digital Marketing Certification Courses
- Cyber Security Certification Courses
- Artificial Intelligence Certification Courses
- Business Analytics Certification Courses
- Data Science Certification Courses
- Cloud Computing Certification Courses
- Machine Learning Certification Courses
- View All Certification Courses
Resources
-
Medicine and Allied Sciences
Colleges
Predictors
Resources
-
Law
Resources
Colleges
-
Animation and Design
Animation Courses
Colleges
Resources
-
Media, Mass Communication and Journalism
Exams
Colleges
Resources
-
Finance & Accounts
Top Courses & Careers
Colleges
Get Answers to all your Questions
- #1.2
- #8.1
- #Match the column
- #Assertion Reason type
- #Short Answer type
- #Long answer type
- #MCQ I
- #MCQ II
- 1.0
- 2.0
- 3.0
- 4.0
- 5.0
- 6.0
- 7.0
- 8.0
- 9.0
- 10.0
- 11.0
- 12.0
- 13.0
- 14.0
- 15.0
- 16.0
- 17.0
- 18.0
- 19.0
- 20.0
- 21.0
- 22.0
- 23.0
- 24.0
- 25.0
- 26.0
- 27.0
- 28.0
- 29.0
- 30.0
- 31.0
- 32.0
- 33.0
- 34.0
- 35.0
- 36.0
- 37.0
- 38.0
- 39.0
- 40.0
- 41.0
- 42.0
- 43.0
- 44.0
- 45.0
- 46.0
- 47.0
- 48.0
- 49.0
- 50.0
- 51.0
- 52.0
- 53.0
- 54.0
- 55.0
- 56.0
- 57.0
- 58.0
- 59.0
- 60.0
- 61.0
- 62.0
- 63.0
- 64.0
- 65.0
- 66.0
- 67.0
- 68.0
- 69.0
- 70.0
- 71.0
- 72.0
- 73.0
- 74.0
- 75.0
- 76.0
- 77.0
An excess of potassium ions makes KCl crystals appear violet or lilac in colour since ________.
(i) some of the anionic sites are occupied by an unpaired electron.
(ii) some of the anionic sites are occupied by a pair of electrons.
(iii) there are vacancies at some anionic sites.
(iv) F-centres are created which impart colour to the crystals.
Answers (1)
The answer is the option (i, iv).
When KCl is heated in vapour of K, anionic vacancies are created as some of the ions leave their lattice site. This chloride ion wants to combine with K vapour to form KCl. For this to happen, loss of electron by potassium atom to form potassium ion occurs. The unpaired free electron gets entrapped in the anion vacancy called F-centre that are responsible for imparting color to crystals. This entrapped electron gains energy due to the visible light falling on the crystal goes to the higher level and when it comes back to the ground state, energy is released in the form of light.
Similar Questions
- 100 g of liquid A (molar mass 140 g mol^-1) was dissolved in 1000 g of liquid B (molar mass 180 g mol^-1).The vapour pressure of pure liquid B was found to be 500 torr.
- 100 turn rectangular coil ABCD (in X-Y plane) is hung from one arm of a balance (shown in figure). A mass 500 g is added to the other arm to balance the weight of the coil.
- 100m long antenna is mounted on a 500m tall building The complex can become a transmission tower for waves with λ (a) ~ 400 m (b) ~ 25 m (c) ~ 150 m (d) ~ 2400 m
Latest Question
- A sum of money under compound interest doubles itself in 4 years. In how many years will it become 16 times itself? Option: 1 1
- A certain loan amounts, under compound interest, compounded annually earns an interest of Rs.1980 in the second year and Rs.2178 in the third year. How much interest did it earn in the first year?
