The following statements describe various properties of a Mercury cell :
(A) It converts energy of combustion into electrical energy
(B) It is rechargeable
(C) The cell reaction involved is Zn(Hg) + HgO(s) \(\rightarrow\) ZnO(s) + Hg(l)
(D) It is a low current device used in hearing aids
Choose the correct answer from the options given below :

Complete the reaction:
\(\text{NH}_2\text{CONH}_2 + \text{H}_2\text{O} \rightarrow \text{ ?}\)

Match List-I with List-II

List-I (Type of cell/Batteries)	List-II (Reaction)
(A) Daniell cell	(I) \(2 H _2(g)+ O _2(g) \rightarrow 2 H _2 O ( l )\)
(B) Fuel Cell	(II) \(Pb ( s )+ PbO _2(s)+2 H _2 SO _4( aq ) \rightarrow 2 PbSO _4(s)+2 H _2 O ( l )\)
(C) Primary Batteries	(III) \(Zn ( s )+ Cu ^{2+}( aq ) \rightarrow Zn ^{2+}( aq )+ Cu ( s )\)
(D) Secondary Batteries	(IV) \(Zn ( Hg )+ HgO ( s ) \rightarrow ZnO ( s )+ Hg ( l )\)

Choose the correct answer from the options given below:

The products for the reaction of KMNO₄ with potassium iodide in acidic solutions are

Match List-l with List-ll:

List-1 (Molecule)	List-II (Van't Hoff Factor)
(A) Glucose	(I) 3
(B) \(K _2 SO _4\)	(II) 5
(C) \(Ca _3\left( PO _4\right)_2\)	(III) 1
(D) \(K _3\left[ Fe ( CN )_6\right]\)	(IV) 4

Choose the correct answer from the options given below:

Identify " \(Y\) " in the following reaction:
\(R-NH_2+HNO_2 \xrightarrow{NaNO_2+HCl} X\xrightarrow{H_2 O} Y+N_2+HCl\)

The product of the following chemical reaction is
Glucose \(\xrightarrow{ Br _2 \text { water }}\)

At a place, the vertical component of Earth's magnetic field is \(\sqrt{3}\) times its horizontal component. If the total intensity of Earth's magnetic field at the place is 0.4 G, then the horizontal component of Earth's magnetic field is:

Arrange the following structures involved in embryogenesis in the correct
sequence.
(A) Zygote
(B) Blastocyst
(C) Blastomeres
(D) Morula
Choose the correct answer from the options given below:

The greatest biodiversity on the earth is seen in :

The area (in sq. units) of the region bounded by the curve \(y=x^5\), the \(x\)-axis and the ordinates \(x=-1\) and \(x=1\) is equal to:

The sum of order and degree of the differential equation \(\left(x^2 \frac{d^2 y}{d x^2}\right)^{\frac{3}{4}}=5\left(\frac{d y}{d x}\right)^2-3\) is equal to :

Answer the question on the basis of passage given below :
Formaldehyde is the first member of the aldehydic series. It is present in green leaves of plants where its presence is supposed to be due to the reaction of \(CO_2\) with water in the presence of sunlight and chlorophyll. Commercially, formaldehyde is obtained by the controlled oxidation of methane in the presence of molybdenum oxide (\(MoO\)) acting as a catalyst. Formaldehyde is a constituent of a number of polymers also called resins. These are non volatile solids or semi solids which are obtained directly from certain plants and can be synthesized in the laboratory.
Question: How is formalin useful?