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Class 10 Chemistry Chapter 18 Salts Full Unit Test 4
Grade 10 Chemistry Chapter 18 Salts Full Unit Test 4
Prepare for your matric Chemistry examination with the Class 10 Chemistry Chapter 18: Salts Full Unit Test 4, part of the Punjab Board 2027 Model Papers and Chapter-Wise Test Series. Developed for students studying under the new syllabus issued by PECTAA Punjab, this full-unit test helps students revise important concepts, practise examination-style questions, and evaluate their understanding of Salts. This Class 10 Chemistry chapter-wise test is a valuable resource for revision, self-assessment, and board examination preparation. Practise the complete unit to strengthen your subject knowledge and improve your exam performance. Visit 786Times.com for more Class 10 Chemistry model papers, chapter-wise tests, and Punjab Board 2027 examination preparation resources.
Chapter: 18
Total Time: 35 min
CHAPTER WISE CLASS TEST
(Test # 4)
Chemistry
Total Marks: 25
NOTE: Four possible answers A, B, C and D to each question are given. The choice which you think is correct, fill that circle in front of that question with Marker or Pen ink. Cutting or filling two or more circles will result in zero mark in that question.
TIME: 10 MinOBJECTIVEMARKS: 8
Q.1:(08)
1.Which base is not soluble in water?
(A) KOH(B) Mg(OH)2(C) NaOH(D) Na2CO3
✔ Answer: (B) Mg(OH)2 (magnesium hydroxide)
2.The reaction of NaOH with HCl is called:
(A) Decomposition reaction(B) Neutralization reaction(C) Combustion reaction(D) Displacement reaction
✔ Answer: (B) Neutralization reaction — NaOH + HCl → NaCl + H2O
3.The shape of the crystal of NaCl is:
(A) Cubic(B) Hexagonal(C) Rhombic(D) Trigonal
✔ Answer: (A) Cubic
4.The shape of NaCl crystal lattice is:
(A) Hexagonal(B) Trigonal(C) Rhombic(D) Face-centered cube
✔ Answer: (D) Face-centered cube
5.The positive ions in salts come from:
(A) Acids(B) Bases(C) Water(D) Oxides
✔ Answer: (B) Bases
6.Which salts are always soluble in water?
(A) Chlorides(B) Sulphates(C) Nitrates(D) Carbonates
✔ Answer: (C) Nitrates (e.g. NaNO3, KNO3)
7.High melting points of ionic compounds are due to:
(A) Weak ionic forces(B) Covalent bonds(C) Strong electrostatic forces(D) Hydrogen bonds
✔ Answer: (C) Strong electrostatic forces
8.Melting points of ionic compounds depend upon:
(A) Colour and solubility(B) Charges on ions and their sizes(C) Temperature and pressure only(D) Mass and volume
✔ Answer: (B) Charges on ions and their sizes
786Times — Chemistry Chapter-18 Test # 4
TIME: 25 MinSUBJECTIVEMARKS: 17
(PART – I)
Q.2 Write short answers to following questions.(6×2=12)
i.Which factors are responsible for the strength of electrostatic forces between ions?
Ans: (1) The charges on the ions and (2) the sizes of the ions. Higher charges and smaller ions give stronger electrostatic forces.
ii.How are ions arranged in NaCl crystal?
Ans: NaCl forms a giant face-centered cubic lattice. Each Na+ ion is surrounded by six Cl− ions and each Cl− ion by six Na+ ions (6 : 6).
iii.Is lead (II) chloride soluble in water? Give comments.
Ans: No. Lead(II) chloride (PbCl2) is insoluble in cold water (it dissolves only slightly in hot water). It is an exception to the rule that chlorides are soluble; AgCl is the other exception.
iv.What factors affect the melting points of ionic compounds?
Ans: The charges on the ions and their sizes. Higher charge and smaller size mean stronger attraction and a higher melting point. Example: MgO (Mg2+, O2−) melts higher than NaCl (Na+, Cl−).
v.Which lead salts are insoluble in water?
Ans: Lead chloride (PbCl2), lead sulphate (PbSO4) and lead carbonate (PbCO3). Lead nitrate, Pb(NO3)2, is soluble.
vi.What is the solubility rule for chlorides?
Ans: All chlorides are soluble in water except silver chloride (AgCl) and lead chloride (PbCl2).
(PART – II)
Note: Attempt the following question.
Q.3: Explain the methods of preparation of two soluble salts.(5)
Ans:
(1) Copper sulphate (acid + insoluble base): Add excess CuO to warm dilute H2SO4 with stirring until no more dissolves. Filter off the excess CuO. Heat the filtrate to the saturation point, cool slowly to get crystals, wash with cold distilled water and dry.
CuO + H2SO4 → CuSO4 + H2O
(2) Sodium chloride (acid + soluble alkali, titration): Put 25 cm3 of NaOH in a flask with phenolphthalein (pink). Add HCl from a burette until the colour just turns colourless (end point) and note the volume. Repeat with the same volumes without indicator, evaporate to the crystallization point and cool to get crystals.
NaOH + HCl → NaCl + H2O
(1) Copper sulphate (acid + insoluble base): Add excess CuO to warm dilute H2SO4 with stirring until no more dissolves. Filter off the excess CuO. Heat the filtrate to the saturation point, cool slowly to get crystals, wash with cold distilled water and dry.
CuO + H2SO4 → CuSO4 + H2O
(2) Sodium chloride (acid + soluble alkali, titration): Put 25 cm3 of NaOH in a flask with phenolphthalein (pink). Add HCl from a burette until the colour just turns colourless (end point) and note the volume. Repeat with the same volumes without indicator, evaporate to the crystallization point and cool to get crystals.
NaOH + HCl → NaCl + H2O
786Times — Chemistry Chapter-18 Test # 4
