(a) State whether the following statements are True or False. Justify your answer.

1. Weak acids have low electrical conductivity.
2. The concentration of hydrogen ions is equal in strong acids and weak acids.

(b) Calculate the percentage of sodium (Na) in Na₂B₄O₇.10H₂O.

1. True
   Reason — Weak acids are partially dissociated in fused or aqueous solution hence allow small amount of electricity to flow through them and thus, have low electrical conductivity.
2. False
   Reason — Acids with a higher concentration of H⁺ (aq) ions are strong acids and acids with a lower concentration of H⁺ (aq) ions are weak acids.

(b) Molecular weight of Na₂B₄O₇.10H₂O
= 2(23) + 4(11) + 7(16) + 20(1) + 10(16)
= 46 + 44 + 112 + 20 + 160
= 382 g

382 g of Na₂B₄O₇.10H₂O contains 46 g of Na

∴ 100 g of Na₂B₄O₇.10H₂O will contain = $\dfrac{46}{382}$ x 100 = 12.04%

Hence, 12.04% of sodium is present in Na₂B₄O₇.10H₂O