Question

please answer fast it's very urgent
class 10 science question​

Answer 1

Answer:

All answers are done

Explanation:

QI.

a.

(i) Aquaregia

(ii) 2CaSO⁴ X 2H2O-->2CaSO⁴ X (1/2)H20+3H20

b.

Ca(OH)2(SLAKED LIME)+Cl2(CHLORINE GAS)-->CaOCl2(CalciumOxyChloride)+H20(water)

c.

1. PARALLEL COMBINATION RESISTOR
2. SERIES COMBINATION RESISTOR

d.

Resistance depends on:-

1. Cross-sectional Area
2. Length
3. Resistivity
4. Conductance
5. Temperature
6. No. of free e-(mobility)

e.

Tungsten

Q2.

(i) Acids undergo dissociation in aqueous solution to form H+ ions. When electricity is passed through an aqueous solution of an acid, the H+ ions reach the cathode and each H+ ion picks up one electron from the cathode to form H2 gas. Because of this reaction, an aqueous solution of acid conducts electricity.

(ii) Dry HCL does not dissociate to give H+ ions. Acids dissociate to give ions only in the aqueous solution. In this, HCL is not in the aqueous form nor the litmus paper is wet, so the colour of the litmus paper does not change.

Q3. Coils of electric toasters and electric irons made of an alloy rather than a pure metal due to the following reasons: The resistivity of an alloy is higher than the pure metal. At high temperatures, the alloys do not oxidize. Alloy does not melt readily and get deformed.

Q4. Sour substances are acidic in nature,i.e, they have acids in them. So, when they are kept in brass or copper vessels, they react with them and form poisonous or better to say toxic elements which may prove harmful for human body.

Q5. A short circuit is an electrical circuit that allows a current to travel along an unintended path with no or very low electrical impedance. This results in an excessive current flowing through the circuit. A common type of short circuit occurs when the positive and negative terminals of a battery are connected with a low-resistance conductor, like a wire. With a low resistance in the connection, a high current will flow, causing the delivery of a large amount of energy in a short period of time.

Q6. Ohm's law states that the current through a conductor between two points is directly proportional to the voltage across the two points.

We know that...V=IR, THEREFORE ACCORDING OHMS LAW-->P=VI=>P=(IR)I=>P=I²R

Graph is provided with my attachment..

Q7. When the excess carbon dioxide gas is passed through the lime water, it turns milky first due to the formation of the calcium carbonate as a precipitate which is insoluble in water and then become colorless due to the formation of calcium bicarbonate.

Hope u Get it...