When sodium dioxonitrate (III) (NaNO₂) dissolves in water H is positive, the process of dissolution is

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65. When sodium dioxonitrate (III) ($\text{NaNO}_2$) dissolves in water $\Delta H$ is positive, the process of dissolution is

• A positive value for the enthalpy change ($\Delta H$) indicates that the reaction absorbs heat from its surroundings. This type of reaction is defined as endothermic.
• The correct option is (b) endothermic.

66. The energy change ($\Delta H$) for the reaction $\text{CO}_{(g)} + \frac{1}{2}\text{O}_{2(g)} \rightarrow \text{CO}_{2(g)}$ is

• We use Hess's Law, which states that the enthalpy change of a reaction