In an electrochemical cell, the salt bridge provides:
A. Voltage
B. Ionic contact and completes the circuit
C. Electron flow
D. Current
Answer: Option B
Solution (By JKSSB Mock Tests)
The salt bridge (often KCl-agar) allows ion migration to maintain electrical neutrality in half-cells, completing the circuit. It prevents direct mixing of electrolytes.
Explanation:
Wood has lower calorific value (~17 kJ/g) compared to coal (~25-35 kJ/g), methane (~55.5 kJ/g), and hydrogen (~142 kJ/g). It contains moisture and oxygen, reducing energy density.
Explanation:
Cu + 4HNO₃ (conc.) → Cu(NO₃)₂ + 2NO₂ + 2H₂O. Dilute HNO₃ gives NO instead of NO₂. Copper does not produce H₂ with HNO₃ because HNO₃ is an oxidizing acid.
Explanation:
Atomic number (Z) is the number of protons in the nucleus, which defines the identity of the element. In a neutral atom, the number of electrons equals Z. Neutrons contribute to mass number but not atomic number. Isotopes have same Z but different number of neutrons. Nucleons are total protons + neutrons = mass number. The modern periodic table is based on atomic number.
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