CBSE Guess > Papers > Question Papers > Class X > 2009 > Science > Science

Q. 13. What is ethanoic acid? Write the formula of the functional group present in this acid. What special name is given to its 5–8% solution in water? How does ethanoic acid react with sodium carbonate? Write the chemical equation of the reaction and common name of the salt produced. 3

Ans.

• Ethanoic acid is the second member of the homologous series of carboxylic acids. The formula of ethanoic acid is CH₃COOH and the functional group present in it is carboxylic acid i.e. —COOH.
• Its 5 – 8% solution in water is called vinegar.
• When ethanoic acid reacts with sodium carbonate, carbon dioxide gas is evolved along with the formation of salt and water. 2CH₃COOH + Na₂CO₃→ 2CH₃COONa + CO₂ + H₂O
  Ethanoic acid Sodium carbonate Sodium ethanoate
  The common name of the salt produced is Sodium acetate.

Q. 14. Draw a schematic diagram of an electric circuit consisting of a battery of six 2 V cells, a 10  resistor, a 20  resistor, a plug key, all connected in series. Calculate the value of current flowing through the 10  resistor and the power consumed by the 20  resistor.

Ans.

R1 = 10  and       R2 = 20
Resultant resistance, R = R1 + R2
R = 10 + 20 = 30
Total voltage = 12 volts
Total current, I = ?
V = I R
I =

Science 2009 Question Papers Class X
Delhi		Outside Delhi		Compartment Delhi		Outside Delhi		Foreign
	Set 1 (PDF)		Set 1 (PDF)		Set 1		Set 1		Set 1 (PDF)
					Set 2		Set 2
					Set 3		Set 3