Question

Q.1 Select the correct word from the words in brackets to complete each sentence: V If pressure on the surface of water increases, its boiling point and freezing point - [increases / decreases). 2. A saturated solution can be converted to an unsaturated solution by (increasing / decreasing) the amount of the solvent. 3. Dissolved air in water contains a [higher/ lower] percentage of oxygen than ordinary air. 4. At low temperatures the solubility of a gas in water is. [less / more] compared to that at ordinary temperatures. 5. Efflorescence occurs when the vapour pressure of the hydrated crystals is (more / less] than the vapour pressure of the atmospheric humidity. on in the brackets. [5]​

Answer 1

Answer:

na ho to kya hua hai kya tu bhi to nhi h kya tu bhi to nhi h to me kya kr rahi ho

Answer 2

Answer:

Answer

a) NH3 is a weak base, which means that some of the molecules will accept a proton from water molecules causing them to dissociate into H+ and -OH ions. The H+ ion will associate with the NH3 to form NH4+. Thus this would look the most like beaker #2. b) HF is a weak acid even though F is strongly electronegative. This is because the H-F molecule can form strong hydrogen bonds with the water molecules and remain in a covalent bond that is harder to dissociate. Thus, beaker #2 is also a good choice for this molecule, as only some of the H-F will dissociate to H3O+ and F- ions. c) CH3CH2CH2OHis a covalent compound and will not dissociate to any appreciable extent, thus, beaker #3 is the correct choice. d) Na2SO4 is a soluble ionic compound and will fully dissociate into ions looking most like beaker #1.

Yes, because when CaCl2 dissociates it will form 3 ions (1 Ca2+ and 2 Cl– ions) whereas NaCl will only dissociate into 2 ions (Na+ and a Cl–) for each molecule. Thus, CaCl2 will generate more ions per mole than 1 mole of NaCl and be a better conductor of electricity.

If the amount of a substance required for a reaction is too small to be weighed accurately, the use of a solution of the substance, in which the solute is dispersed in a much larger mass of solvent, allows chemists to measure the quantity of the substance more accurately.