i) Aldehyde, (ii) Carboxylic acid.

Non-metal (lustrous) = Iodine (I)
Metal (non-lustrous) = Sodium (Na)

In a physical change, no new substance is formed. In a chemical change, new substance is formed.

As the wire is bent in the form of a closed circle, it will be have like two resistors of 5\(\Omega \) each, connected in parallel. Therefore, the equivalent resistance can be calculated as:
\(\frac { 1 }{ R_{ eq } } =\frac { 1 }{ { R }_{ 1 } } +\frac { 1 }{ { R }_{ 2 } } \)
\(\frac { 1 }{ R_{ eq } } =\frac { 1 }{ 5 } +\frac { 1 }{ 5 } \)=\(\frac { 1 }{ R_{ eq } } =\frac { 2 }{ 5 } \)
\(\frac { 1 }{ R_{ eq } } =\frac { 5 }{ 2 } =2.5\Omega \)
The effective resistance between the two points at the ends of an diameter of the circle is 2.5 \(\Omega \).

\( \therefore Power=\frac{1}{Focal length}=-\frac{1}{2}=-0.50 D\)
Negative sign arises due to the divergent nature of concave lens.

When sunlight passes through the canopy of a dense forest, the tiny water droplets in the mist scatter the sun light.

(a) Walking and cycling for commute.
(b) Using jute/cloth shopping bag.
(c) using public transport.
(d) Switching off light/fans in unoccupied rooms.

It is believed that features in dinosaurs might have provided insulation in cold weather but later on became useful for flights in birds.

CH₃CH₂OH, ethanol

Pancreatic trypsin

Cinnabar, Hgs

Egg shells contain calcium carbonate When nitric acid is added to it, carbon dioxide gas is evolved. The reaction can be given as
\(CaCO_3+2HNO_3\rightarrow Ca(NO_3)_2+H_2O+CO_2\)

The above reaction is a decomposition reaction. The symbol \(\Delta\) represents the heat and the MnO₂ represents that it acts as a catalyst for the decomposition reaction to take place. Since the decomposition takes place in presence of heat, the reaction is thermal decomposition.

Element X is copper and the black coloured compound is copper (Il) oxide.
2Cu(s) + O₂(g) \( \xrightarrow[]{Heat }\) 2CuO(s)
X(Brown)                  Copper (II) oxide (Black)

(i) Salt that contains water of crystallisation.
(ii)Washing soda - Na₂CO₃.10H₂O
Gypsum - CaSO₄.2H₂O
Plaster of pans - CaSO₄.\(1\over 2\)H₂O

(i) Gold and silver are most malleable metal and most ductile metal,
(ii) Silver is the best conductor of heat and lead is the poorest conductor of heat.
(iii) Metal with highest melting point - Tungsten, iron. Metal with lowest melting point - Gallium, Cesium.

(i) Solution Y is a stronger acid.
(ii) Strong acid: An acid which dissociates completely in water and produces a large amount of hydrogen ions. e.g., HCI
Weak acid: An acid which dissociates partially in water and produces a small amount of hydrogen ions. CH₃COOH.

It is given that: Voltage (V) = 2.50 V
Current (I) = 750 mA = 0.75 A
The bulb is lighted for 4 hours.
Thus,
(i) Power generated (P) = VI = 2.50\(\times\) 0.75 = 1.87 W
(ii) Resistance (R) = \(\frac { V }{ I } =\frac { 2.5 }{ 0.75 } =3.33\Omega \)
(iii) Energy consumed in 4 hours = Power\(\times\)Time = P\(\times\)t =1.87\(\times\)4 = 7.48  Wh

(i) An aqueous solution with pH value 7.0 is neutral in nature.

(ii) The pH value is given by the formula:

           \(pH=-log[H^+]\)

           \(pH+-(-2)\ log\ 10\)

or, pH = 2

(iii) 1 M NaOH solution has a higher pH value.  This because \(pH=-log[H^+]\ NaOH\) dissociates to give hydroxyl ion, not hydrogen ions.  On the other hand, HCl is a strong acid and dissociates to give hydrogen ions.

(b) CB=-uCF = -fCB=-v 
The relation between u, v and f is given by the lens formula:
\(\frac { 1 }{ f } =\frac { 1 }{ v } -\frac { 1 }{ u } \)
As both u and v are negative the above equation will change to
\(\frac { 1 }{ f } =\frac { 1 }{ (-v) } -\frac { 1 }{ (-u) } \)
\(\frac { 1 }{ f } =\frac { -1 }{ v } +\frac { 1 }{ u } \)
\(\Rightarrow \frac { 1 }{ f } =\frac { 1 }{ u } -\frac { 1 }{ v } \)
We know that the focal length of a concave lens is negative, so the above equation will be changed to
\(\frac { 1 }{ -f } =\frac { 1 }{ u } -\frac { 1 }{ v } \)
\(\Rightarrow \frac { 1 }{ f } =\frac { 1 }{ v } -\frac { 1 }{ u } \)
(c) Magnification m=-1 
v = + 40 cm (real and inverted) 
Nature of the lens = ? 
Power of the lens, P =?
\(\frac { v }{ u } =m\Rightarrow \frac { +40 }{ u } =-1\)
40=-u ⇒ u = -40 cm 
According to the lens formula,
\(\frac { 1 }{ f } =\frac { 1 }{ v } -\frac { 1 }{ u } \)
\(\Rightarrow \frac { 1 }{ f } =\frac { 1 }{ 40 } -\frac { 1 }{ -40 } =\frac { 1 }{ 40 } +\frac { 1 }{ 40 } =\frac { 2 }{ 40 } =\frac { 1 }{ 20 } \)
f = +20 cm 
fis +ve thus the lens is convex
\(P=\frac { 1 }{ f(metres) } =\frac { 1\times 100 }{ 20 } =+5D\)
Since power of lens is positive, lens will be converging in nature.

(i) Yes.If a convex lens of focal length 10cm is covered one half with a black paper, it can produce an image of the complete object between F₂ and 2F₂.The rays of light coming from the object get refracted by the upper half of the lens. The image formed will be real, inverted and diminished.

(ii)Object height, h₁=4cm
Focal length, f=+20cm
Object distance, u=-15cm
Image distance, v=?
Image height, h₂=?
By lens formula,
\({1\over f}={1\over v}-{1\over u}\)
\(\Rightarrow\ {1\over v}={1\over f}+{1\over u}={1\over +20}+{1\over -15}={1\over 20}-{1\over 15}\)
\(\Rightarrow\ {1\over V}={3-4\over 60}={-1\over 60}\)
v=-60cm
Negative sign of v shows that the image is virtual.

(a) The eating up of metals by the action of air and moisture on their surface is called corrosion.
      (i) Metal which does not corrode on being kept in the atmosphere is gold.
     (ii) Metal which corrodes on being kept in the atmosphere is iron.
(b) Take three boiling tubes and label them as A, B, and C. Place clean iron nails, free from rust, in each tube. Add water to tube A in such a manner that some parts of the nails are exposed to air and seal it with the help of a rubber cork. Add boiled water to tube B in such a way that the nails are completely submerged. Then, pour some amount of kerosene oil in the tube and seal it with the help of a rubber cork. Add anhydrous calcium chloride to tube C and then seal it. Leave the tubes undisturbed for two weeks and observe the changes. 

Various plant hormones and their effects are as follows:
(i) Auxin : Promotes cell elongation and thus promotes growth of a plant part.
(ii) Gibberellins : Promotes growth.
(iii) Cytokinin :  Promotes cell division and thus promotes growth.
(iv) Abscissic acid : Inhibits growth and is responsible for shedding or older parts.

The differences between the movement in sensitive plant and our legs are as follows :