Download App

The d & f Block Elements — Chemistry STD 12 Science — Question

Gujarat BoardEnglish MediumSTD 12 ScienceChemistryThe d & f Block Elements5 Marks
Question
  1. Complete the following chemical equations:
  1. $\text{Cr}_{2}\text{O}_{7}^{2-}\text{(aq)}+\text{H}_{2}\text{S}\text{(g)}+\text{H}^{+}\text{(aq)}\rightarrow$
  2. $\text{Cu}^{2+}\text{(aq)}+\text{I}^{-}\text{(aq)}\rightarrow$
  1. How would you account for the following:
  1. The oxidising power of oxoanions are in the order $VO^+_2 < Cr_2O^{2–}_7 –_4.$
  2. The third ionisation enthalpy of manganese (Z = 25) is exceptionally high.
  3. $Cr^{2+}$ is a stronger reducing agent than $Fe^{2+}.$
✓

Answer

  1.  
  1. $\text{Cr}_{2}\text{O}_{7}^{2-}+\text{3H}_{2}\text{S}+\text{8H}^{+}\rightarrow\text{2Cr}^{3+}+\text{7H}_{2}\text{O}+\text{3S}$.
  2. $\text{2Cu}^{2+}+\text{4I}^{-}\rightarrow\text{Cu}_{2}\text{I}_{2}+\text{I}_{2}$.
  1.  
  1. It is due to increasing stability of lower species to which they are reduced.
  2. Because removing $3^{rd} e^-$ from extra stable $3d^5$ configuration is difficult in case of Mn.
  3. Because $d^3$ of $Cr^{2+} $is more stable than $d_5$ of $Fe^{3+}.$

Need a full question paper?

Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.

Start Generating Free

Explore more

More "5 Marks Questions" from The d & f Block Elements→The d & f Block Elements — all question types→Chemistry STD 12 Science question papers→Gujarat Board STD 12 Science question papers→Gujarat Board question paper generator→

Similar questions

(a) What is van't Hoff factor? Explain.
(b) Write the equation of molecular number properties including van't Hoff factor.
→
Match the catalysts given in Column I with the processes given in Column II.
 
Column I (Catalyst)
 
Column II (Process)
(i)
Ni in the presence of hydrogen
(a)
Zieglar Natta catalyst
(ii)
$Cu_2Cl_2$
(b)
Contact process
(iii)
$V_2O_5$
(c)
Vegetable oil to ghee
(iv)
Finely divided iron
(d)
Sandmeyer reaction
(v)
$TiCl_4 + Al (CH_3)_3$
(e)
Haber’s Process
 
 
(f)
Decomposition of $KClO_3$
→
Attempt any five of the following:
(a) Why are polysaccharides considered non-sugars?
(b) What is meant by invert sugars?
(c) Write the name of the component of starch which is water-soluble.
(d) Write the products obtained after hydrolysis of DNA.
(e) Name the deficiency disease resulting from lack of vitamin A and E in the diet.
(f) Which vitamin is linked with anti-sterility?
(g) a. What is the difference between a nucleoside and nucleotide?
     b. What products would be formed when a nucleotide from DNA containing thymine is hydrolysed?
→
Explain the structure of fructose.
→
Describe graphically the experimental method of measuring the conductivity of electrolyte solutions (ionic solution).
→
  1. When concentrated sulphuric acid was added to an unknown salt present in a test tube a brown gas (A) was evolved. This gas intensified when copper turnings were added to this test tube. On cooling, the gas (A) changed into a colourless solid (B).
  1. Identify (A) and (B).
  2. Write the structures of (A) and (B).
  3. Why does gas (A) change to solid on cooling?
  1. Arrange the following in the decreasing order of their reducing character:
HF, HCl, HBr, HI
  1. Complete the following reaction:
$\text{XeF}_4+\text{SbF}_5\xrightarrow{\ \ \ \ \ \ \ \ }$
→
Answer the following questions:
Write balanced equations to represent what happens when.
  1. $Cu^{2+}$​​​​​​​ is treated with KI.
  2. Acidified potassium dichromate solution is reacted with iron (II) solution. (ionic equation).
→
Mr. Roy, the principal of one reputed school organised a seminar in which he invited parents and principals to discuss the serious issue of diabetes and depression in students.They all resolved this issue by strictly banning the junk food in schools and to introduce healthy snacks and drinks like soup, lassi, milk etc. in school canteens. They also decided to make compulsory half an hour physical activities for the students in the morning assembly daily. After six months, Mr. Roy conducted the health survey in most of the schools and discovered a tremendous improvement in the health of students.

After reading the above passage, answer the following:
  1. What are the values (at least two) displayed by Mr. Roy?
  2. As a student, how can you spread awareness about this issue?
  3. What are tranquillizers? Give an example.
  4. Why is use of aspartame limited to cold foods and drinks?
→
Differentiate between $1^{\circ}, 2^{\circ}$ and $3^{\circ}$ alcohols by catalytic dehydrogenation.
→
Write the formulas for the following coordination compounds:
a. Tetraammineaquachloridocobalt(III) chloride
b. Potassium tetrahydroxidozincate(II)
c. Potassium trioxalatoaluminate(III)
d. Dichloridobis(ethane-1, 2-diamine)cobalt(III)
e. Tetracarbonylnickel(0)
→