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What is the atomic mass of sodium?(1) 22 g/mol (2) 23 g/mol (3) 11 g/mol (4) 20 g/mol

Answer: (2) 23 g/mol The total number of neutrons and protons of an atom is called atomic mass. The atomic mass unit is Dalton. It is... View Article

Calculate the molar mass of Nitric acid (HNO3). Atomic mass of H=1U, N=14u, O=16u

Answer: The molar mass of the chemical substance is equal to the sum of the atomic mass of the individual atoms. The smallest unit of a... View Article

(1) Why do transition elements show variable oxidation states?(2) Name the element showing maximum number of oxidation states among the first series of transition metals from Sc(Z=21) to Zn(Z=30).(3) Name the element which shows only +3 oxidation state.

Answer: (1) Transition elements (also known as transition metals) are elements that have partially filled d orbitals. IUPAC defines transition... View Article

Tunica corpus theory is connected with (1) root apex (2) root cap (3) shoot apex (4) secondary growth

Answer: (3) The theory of tunica corpus, given by Schmidt (1927), is connected to the apical meristem of the shoot apex or stem. Similar to it,... View Article

Which is the largest 3 digit number ?

Answer: The smallest 3-digit number is 100 and the largest 3-digit number is 999.... View Article

Find the total surface area of a solid hemisphere of radius r.

Answer: If a plane that passes through a sphere's centre splits the sphere into two equal parts, each part is called a hemisphere.The area... View Article

What is meant by a positive work, negative work and zero work? Illustrate your answer with example?

Answer: Work is said to be done when a force applied to an object moves that object. When force and displacement are in the same direction,... View Article

When ethyne is passed through a red hot tube, then formation of benzene takes place:?Hof(C2H2)(g) = 230kJmol?1?Hof(C6H6)(g) = 85kJmol?1Calculate the standard heat of trimerisation of ethyne to benzene.C2H2(g) ? C6H6(g)(1) 205 kJmol?1(2) 605 kJmol?1(3) -605 kJmol?1(4) -205 kJmol?1

Answer: (3) To calculate the standard heat of trimerisation of ethyne to benzene consider a formula ΔH0trimerisation = ΔHof(C6H6) -... View Article

Define limiting molar conductivity. Why conductivity of an electrolyte solution decreases with the decrease in concentration?

Answer: The molar conductivity of a solution at infinite dilution is known as limiting molar conductivity. In other words, When the... View Article

Leguminous plants are important in agriculture because(1) They are disease resistant(2) They have high amount of proteins(3) They require less amount of nitrogen for growth(4) Nitrogen-fixing bacteria are symbiotically associated in them

The correct answer is (4) Nitrogen-fixing bacteria are symbiotically associated with them Those plant that fixes atmospheric nitrogen to the soil... View Article

Fresh milk has a pH of 6. How do you think the pH will change as it turns into curd?(1) pH will reduce(2) pH will increase(3) It become same as milk(4) None of the above

Answer: (1)pH will reduce The pH value of milk is 6 since it is acidic in nature. When the milk is converted into curd due to the action of... View Article

Lead nitrate crystals on strong heating decompose to form lead monoxide, nitrogen dioxide gas and oxygen gas. Explain

Answer: When lead nitrate is heated it decomposes to form a lead oxide, nitrogen dioxide and oxygen. Thus, lead nitrate on decomposition gives... View Article

The value of 1 amu is equal to(1) 1.66 ×10 ?8 g.(2) 1.66 ×10 ?4 g.(3) 1.66 ×10 ?16 g.(4) 1.66 ×10 ?24 g.

Answer: (4) Full form of amu is the atomic mass unit. Mass of 1 atom = 12amu 1amu = (Mass of 1 126C atom)/12 1amu = (1.994 x 10-23)/12 1amu =... View Article

What is the role of septum in heart?

Answer: The septum is also known as an atrial septum or ventricular septum. The septum's primary function in the heart is to isolate the two... View Article

Give reason: Phenol is more acidic than that of ethanol.

Answer: The acidic substance has the tendency to produce H+ ions when dissolved in water. Both phenol and ethanol are weak acids. However, the... View Article

What are unisexual and bisexual flowers? Give two examples of each.

Answer: The flowers which contain only the male or female reproductive organs are called unisexual flowers. They are called incomplete... View Article

What are lyophilic and lyophobic sols? Give one example of each type. Why are hydrophobic sols easily coagulated?

Answer: Lyophilic sols When sols are produced directly by mixing substances in an effective dispersing medium are called lyophilic sols.... View Article

Edible portion of Mango is(1) Epicarp(2) Endocarp(3) Mesocarp(4) None of the above

Answer: (3) The mesocarp is the pericarp mid-layer between the exocarp and the endocarp. The mesocarp, in mango, is the nutritious, fleshy part... View Article

In a triangle ABC , if 3 angleA = 4 angleB = 6 angleC, calculate the angle.

Answer: Given parameters In ΔABC, 3∠A = 4∠B= 6∠C Let us consider x = 3∠A = 4∠B = 6∠C x = 3∠A ∠A = x/3......................(1) x = 4∠B... View Article

Which of the following is not a greenhouse gas? (1) Carbon dioxide (2) Sulphur dioxide (3) Methane (4) Nitrogen

Answer: (4) A greenhouse gas is a gas that produces heat in the atmosphere as it increases. It also gets stuck in the environment and can not... View Article